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Computer Assisted Interviewing for SAMHSA's National Household Survey on Drug Abuse

7. Effect of ACASI Experimental Factors on Prevalence and Data Quality: 1997 Field Experiment

In this chapter, we examine the effect of audio computer-assisted self-interviewing (ACASI) experimental factors on reported prevalence, inconsistencies in reporting, time required to complete the interview, and breakoff rates. In addition, we examine the effect that the experimental factors had on respondents' ability to complete the interview and their attitudes about the survey task. Sections 7.1 through 7.3 contain the descriptive results; in Sections 7.4 and 7.5, we present the results of the statistical tests.

Because all respondents did not answer the same questions, it was necessary to create a set of edited recency of use variables for constructing the lifetime, 12-month, and 30-day prevalence of use estimates. This was done in three stages. In the ACASI application, all respondents had multiple chances to report use. For example, even respondents who did not receive multiple use questions could report that they had used alcohol in the past 30 days and subsequently report that they had used it on 0 days in the past 30 days. And some respondents who were in the multiple use treatment category were asked twice about their use in a particular time period. Thus, we first created a series of recodes for 30-day and 12-month use that documented whether the respondent was consistent or inconsistent in reporting use in these time periods. For example, we created a variable MU30ALC that had the following four levels:

For the random half of the respondents who received consistency checks during the interview and who had inconsistent data (e.g., MU30ALC = 2 or 3), we created a variable that documented the outcome of the consistency check. This variable also had four levels based on the path through the questionnaire and classified the respondent as either a user or nonuser for the period in question. The edited recency variables were created from these intermediate recodes.

This process resulted in our inability to determine the recency of use of some respondents; therefore, we had a residual category of indeterminate answers. In the NHSDA series of surveys, a similar logical editing procedure is used; however, before the final estimates are made, all indeterminate recency of use answers are removed by statistical imputation. We did not use any statistical imputations for the field experiment analysis. Therefore, when we compared 1997 field experiment data with data from the 1997 NHSDA Quarter 4, we used the recency variable thatwas edited but not imputed because it was the most analogous paper-and pencil interview (PAPI) comparison variable.

For cigarettes, there is one final important difference between the field experiment and the 1997 NHSDA that affects the prevalence estimates. In the field experiment, we routed respondents who had only had one or two puffs of a cigarette to the next section after they had reported their age at first use.

In addition to the edited variables, we also produced tables of weighted estimates using raw variables that were created using the most direct question on recency of use. For example, respondents in Treatments 5, 6, 7, and 8 who answered "yes" to the question "During the past 30 days, have you _______?" were counted as 30-day users even if they later indicated having used 0 days in the past 30 days. For the comparison group, we used answers to the recency question "How long has it been since you last used ______?" to create the raw variables. Estimates using raw variables are given in RTI (1998).

Exhibit 7.1 summarizes the findings for the main effects of the ACASI experimental factors by showing the ratios of the prevalence estimates by the level of the main effects. In the following section, each factor is discussed separately, followed by the results of the modeling.

7.1 Structure of Contingent Questioning

As described in Chapter 5, a random half of the respondents received a single gate question and a random half received three gate questions. We hypothesized that using multiple gate questions would result in fewer inconsistent reports and higher reports of prevalence of use, particularly for lifetime and 12-month use. We speculated that lifetime prevalence might be higher because (a) respondents could first deny more proximate use, which other research (e.g., Turner, Lessler, & Devore, 1992a) has shown to be a more sensitive behavior, and (b) it would prevent routing respondents who inadvertently answered "no" to a single gate question to the next section, thereby missing a chance to gather information about their use. In addition, we felt that having multiple gate questions that permitted the respondent to focus on each reference period individually would reduce inconsistencies in reporting.

7.1.1 Prevalence Estimates

Exhibits 7.1.1 through 7.1.15 display the weighted estimates of prevalence by selected demographic variables. For cigarette use, a mixed pattern was observed in the overall estimates, with single gate questions sometimes yielding higher reports and sometimes yielding lower reports. Differences between the two approaches were not large in any case, and most ratios were close to one. A similar pattern was observed for alcohol use. For marijuana, cocaine, and any illicit drug use, the single gate questions tended to yield higher reports of use. These findings were not in the direction hypothesized prior to the field experiment.

7.1.2 Inconsistencies in Reporting

We also examined inconsistencies in reporting by identifying the number of people who had a chance to give an inconsistent report. We confined this detailed analysis to cigarettes, alcohol, and marijuana so that we would have enough people to make meaningful comparisons. Exhibits 7.1.16 to 7.1.20, contrary to our expectations, indicate that multiple gate questions resulted in a higher percentages of inconsistent reports in most of the cases compared to single gate questions. The denominators (N) of the percentages included people who were able to get to the questions (i.e., they were not routed to the next section at a previous question), where they recorded the number of days of use within the particular time period. For past 12-month use, respondents answering the treatment versions with no multiple use questions had no chance of recording an inconsistent response.

7.1.3 Operational Aspects of Reporting Under Alternative Contingent Questioning Strategies

Time required to complete the interview. The average length of time required to complete each drug section with multiple gate questions was slightly higher than the time required to complete each drug section with a single gate question. However, the differences were not large (see Exhibit 7.1.21).

Exhibit 7.1 Ratio of Prevalence Estimates for ACASI Experimental Factors Overall and by Age Group

 

Overall

 

18+ Years Old

 

12 to 17 Years Old

Factor

Lifetime

12 Month

30 Day

 

Lifetime

12 Month

30 Day

 

Lifetime

12 Month

30 Day

Cigarettes

 

Multiple Gate Qs: Single/Multiple

1.07

0.87

1.03

 

1.08

0.87

1.03

 

0.94

0.99

1.07

Multiple 30-Day and 12-Month Qs:

Absent/Present
Consistency Checks:
Absent/Present


1.06

0.94


0.88

0.84


0.70

0.77

 


1.05

0.93


0.84

0.82


0.67

0.76

 


1.14

1.05


1.48

1.09


1.16

0.92

Alcohol

Multiple Gate Qs: Single/Multiple

0.97

0.90

0.94

 

0.97

0.90

0.94

 

1.00

1.00

1.05

Multiple 30-Day and 12-Month Qs:

Absent/Present
Consistency Checks:
Absent/Present


1.01

0.97


0.94

0.91


1.07

0.85

 


1.00

1.03


0.92

1.03


1.06

0.89

 


1.09

0.97


1.07

0.90


1.12

0.85

Marijuana

Multiple Gate Qs: Single/Multiple

1.01

1.63

1.45

 

1.00

1.76

1.48

 

1.18

1.12

1.32

Multiple 30-Day and 12-Month Qs:

Absent/Present
Consistency Checks:
Absent/Present


0.90

0.99


0.80

0.94


1.31

0.64

 


0.88

0.99


1.76

0.94


1.31

0.59

 


1.14

1.02


1.48

0.94


1.16

0.85

Cocaine

Multiple Gate Qs: Single/Multiple

1.93

2.64

1.13

 

1.94

2.76

1.00

 

1.92

1.86

3.77

Multiple 30-Day and 12-Month Qs:

Absent/Present
Consistency Checks:
Absent/Present


0.68

0.62


1.47

0.75


0.98

1.09

 


0.66

0.63


1.51

0.74


1.18

0.95

 


0.93

0.74


0.98

0.96


0.19

4.68

Any Illicit Drug1

Multiple Gate Qs: Single/Multiple

1.14

1.29

1.45

 

1.13

1.34

1.51

 

1.18

1.06

1.23

Multiple 30-Day and 12-Month Qs:

Absent/Present
Consistency Checks:
Absent/Present


0.90

0.99


0.92

0.92


1.30

0.64

 


0.89

0.99


0.90

0.93


1.35

0.60

 


1.11

0.98


1.10

0.84


1.21

0.76

1Any illicit drug includes marijuana, cocaine, crack, heroin, inhalants, hallucinogens, and nonmedical use of analgesics, sedatives, stimulants, and tranquilizers.

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures: 1997 Field Experiment.


Breakoff rates. In Exhibit 7.1.22, we compared the percentage of cases that were reported as a breakoff (even if the interviewer went on to finalize the case as a completed interview) by the treatment versions (single gate vs. multiple gate questions). Then we compared the percentage of finalized breakoff cases among single rate and multiple gate questions. The data show no meaningful difference between the breakoff rates for single gate and multiple gate questions.

Respondent reactions as reported in the debriefing questionnaire. Exhibit 7.1.23 presents an analysis of items from the respondent debriefing questions to see whether multiple gate questions had any effect on respondent reactions to the computer-assisted interviewing (CAI) NHSDA interview. The exhibit includes data from five items. About 87% of the respondents who were administered the multiple gate questions indicated that they were able to enter answers easily into the computer compared to 90% of the respondents who were administered the single gate questions. There was no important difference between the responses for single gate and multiple gate questions for the other items, including respondents' difficulty in using the computer, their interest in the interview, and the accuracy and completeness of their answers.

Detailed Exhibits for Section 7.1

Exhibit 7.1.1 Lifetime Use of Cigarettes, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

74.18%

69.38%

71.96%

70.87%

         

Age Group

       

    12 to 17

43.20%

46.04%

44.48%

36.05%

    18+

77.88%

72.04%

75.18%

74.94%

         

Gender

       

    Male

75.71%

72.64%

74.25%

74.74%

    Female

72.82%

66.14%

69.83%

67.25%

         

Race/Ethnicity

       

    Hispanic

64.34%

63.15%

63.68%

55.82%

    Non-Hisp., Black

62.65%

66.11%

64.30%

61.62%

    Non-Hisp., All Other Races

76.82%

70.65%

74.04%

73.81%

         

Education1

       

    < High School

84.90%

68.25%

77.83%

70.28%

    High School

78.43%

81.58%

79.73%

76.65%

    > High School

75.01%

67.77%

71.35%

75.27%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.2 Lifetime Use of Alcohol, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

82.01%

84.50%

83.16%

82.15%

         

Age Group

       

    12 to 17

44.89%

44.92%

44.90%

38.01%

    18+

86.45%

89.01%

87.63%

87.31%

         

Gender

       

    Male

80.10%

88.20%

83.95%

87.07%

    Female

83.70%

80.81%

82.41%

77.55%

         

Race/Ethnicity

       

    Hispanic

70.87%

77.01%

74.26%

69.45%

    Non-Hisp., Black

65.91%

65.13%

65.54%

72.35%

    Non-Hisp., All Other Races

85.51%

88.92%

87.04%

84.98%

         

Education1

       

    < High School

84.79%

78.92%

82.30%

77.22%

    High School

81.23%

89.67%

84.73%

85.83%

    > High School

91.16%

91.17%

91.16%

91.48%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.3 Lifetime Use of Marijuana, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

35.36%

34.98%

35.18%

34.96%

         

Age Group

       

    12 to 17

22.08%

18.70%

20.56%

16.10%

    18+

36.94%

36.84%

36.90%

37.17%

         

Gender

       

    Male

39.35%

36.06%

37.78%

40.79%

    Female

31.81%

33.91%

32.75%

29.51%

         

Race/Ethnicity

       

    Hispanic

38.98%

39.12%

39.06%

24.59%

    Non-Hisp., Black

27.72%

34.49%

30.95%

31.43%

    Non-Hisp., All Other Races

36.39%

34.63%

35.60%

36.48%

         

Education1

       

    < High School

26.55%

29.61%

27.85%

32.84%

    High School

36.22%

35.84%

36.06%

36.60%

    > High School

41.12%

39.19%

40.15%

38.91%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.4 Lifetime Use of Cocaine, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

19.18%

9.93%

14.91%

10.03%

         

Age Group

       

    12 to 17

3.64%

1.90%

2.86%

3.13%

    18+

21.04%

10.84%

16.32%

10.84%

         

Gender

       

    Male

26.68%

9.70%

18.60%

12.47%

    Female

12.53%

10.15%

11.46%

7.76%

         

Race/Ethnicity

       

    Hispanic

15.81%

18.52%

17.30%

7.32%

    Non-Hisp., Black

15.27%

4.02%

9.90%

7.57%

    Non-Hisp., All Other Races

20.08%

10.12%

15.59%

10.70%

         

Education1

       

    < High School

36.36%

8.47%

24.51%

9.52%

    High School

17.54%

9.64%

14.27%

10.37%

    > High School

18.50%

12.09%

15.26%

11.58%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.5 Lifetime Use of Any Illicit Drug, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

46.26%

40.75%

43.72%

37.50%

         

Age Group

       

    12 to 17

33.48%

28.32%

31.15%

20.45%

    18+

47.79%

42.17%

45.19%

39.49%

         

Gender

       

    Male

49.68%

37.16%

43.72%

43.44%

    Female

43.23%

44.32%

43.72%

31.94%

         

Race/Ethnicity

       

    Hispanic

46.31%

42.58%

44.25%

28.63%

    Non-Hisp., Black

34.56%

38.82%

36.59%

33.40%

    Non-Hisp., All Other Races

48.23%

40.92%

44.93%

38.99%

         

Education1

       

    < High School

54.09%

32.81%

45.05%

37.22%

    High School

46.31%

44.03%

45.36%

38.42%

    > High School

46.79%

43.49%

45.12%

40.92%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.6 Past 12-Month Use of Cigarettes, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

29.24%

33.46%

31.19%

33.52%

         

Age Group

       

    12 to 17

22.74%

23.05%

22.88%

25.18%

    18+

30.02%

34.65%

32.16%

34.49%

         

Gender

       

    Male

38.14%

33.32%

35.85%

34.17%

    Female

21.34%

33.59%

26.82%

32.91%

         

Race/Ethnicity

       

    Hispanic

34.51%

23.70%

28.55%

32.69%

    Non-Hisp., Black

24.35%

36.07%

29.94%

35.19%

    Non-Hisp., All Other Races

29.69%

34.01%

31.64%

33.29%

         

Education1

       

    < High School

57.88%

28.04%

45.20%

34.76%

    High School

24.86%

51.87%

36.04%

41.55%

    High School

24.44%

26.87%

25.67%

29.70%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.7 Past 12-Month Use of Alcohol, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

65.11%

71.99%

68.28%

64.95%

         

Age Group

       

    12 to 17

36.42%

36.49%

36.45%

32.74%

    18+

68.54%

76.03%

72.00%

68.71%

         

Gender

       

    Male

62.83%

77.43%

69.78%

70.07%

    Female

67.12%

66.58%

66.88%

60.15%

         

Race/Ethnicity

       

    Hispanic

54.39%

71.17%

63.65%

57.10%

    Non-Hisp., Black

44.86%

56.29%

50.31%

53.54%

    Non-Hisp., All Other Races

69.27%

75.01%

71.86%

67.64%

         

Education1

       

    < High School

57.94%

50.08%

54.60%

48.54%

    High School

66.10%

77.46%

70.80%

68.12%

    > High School

74.15%

81.74%

77.99%

75.47%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.8 Past 12-Month Use of Marijuana, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

12.47%

7.64%

10.24%

9.36%

         

Age Group

       

    12 to 17

17.56%

15.62%

16.69%

12.97%

    18+

11.86%

6.73%

9.49%

8.94%

         

Gender

       

    Male

17.80%

9.62%

13.91%

13.08%

    Female

7.75%

5.68%

6.82%

5.88%

         

Race/Ethnicity

       

    Hispanic

10.71%

16.66%

13.99%

10.21%

    Non-Hisp., Black

8.84%

7.73%

8.31%

9.60%

    Non-Hisp., All Other Races

13.21%

6.67%

10.26%

9.25%

         

Education1

       

    < High School

10.89%

4.19%

8.05%

14.87%

    High School

9.05%

7.95%

8.59%

10.10%

    > High School

14.43%

6.70%

10.52%

6.30%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.9 Past 12-Month Use of Cocaine, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

3.69%

1.40%

2.63%

1.60%

         

Age Group

       

    12 to 17

2.23%

1.20%

1.77%

2.54%

    18+

3.87%

1.42%

2.74%

1.49%

         

Gender

       

    Male

4.80%

1.16%

3.07%

2.10%

    Female

2.71%

1.64%

2.23%

1.13%

         

Race/Ethnicity

       

    Hispanic

6.72%

2.91%

4.62%

1.56%

    Non-Hisp., Black

4.31%

2.41%

3.40%

2.98%

    Non-Hisp., All Other Races

3.37%

1.05%

2.33%

1.36%

         

Education1

       

    < High School

7.53%

2.01%

5.19%

1.87%

    High School

1.59%

2.25%

1.86%

2.03%

    > High School

4.41%

0.82%

2.59%

1.01%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.10 Past 12-Month Use of Any Illicit Drug, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

16.92%

13.10%

15.16%

10.28%

         

Age Group

       

    12 to 17

23.70%

22.22%

23.03%

14.54%

    18+

16.10%

12.07%

14.24%

9.78%

         

Gender

       

    Male

20.97%

11.04%

16.24%

13.87%

    Female

13.32%

15.16%

14.14%

6.93%

         

Race/Ethnicity

       

    Hispanic

17.84%

22.11%

20.20%

12.33%

    Non-Hisp., Black

14.43%

10.90%

12.74%

9.99%

    Non-Hisp., All Other Races

17.27%

12.56%

15.15%

10.16%

         

Education1

       

    < High School

15.60%

6.03%

11.53%

14.57%

    High School

11.81%

16.32%

13.68%

10.63%

    > High School

19.69%

11.25%

15.41%

7.71%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.11 Past 30-Day Use of Cigarettes, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

26.61%

25.73%

26.20%

30.45%

         

Age Group

       

    12 to 17

16.62%

15.49%

16.11%

18.56%

18+

27.80%

26.89%

27.38%

31.84%

         

Gender

       

    Male

34.95%

21.26%

28.43%

31.10%

    Female

19.20%

30.17%

24.11%

29.84%

         

Race/Ethnicity

       

    Hispanic

30.09%

21.46%

25.33%

28.86%

    Non-Hisp., Black

18.94%

31.21%

24.79%

33.03%

    Non-Hisp., All Other Races

27.65%

25.15%

26.53%

30.13%

         

Education1

       

    < High School

57.32%

26.00%

44.01%

34.23%

    High School

23.07%

45.24%

32.25%

38.72%

    > High School

21.31%

17.08%

19.17%

26.50%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.12 Past 30-Day Use of Alcohol, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

47.35%

50.27%

48.70%

52.21%

         

Age Group

       

    12 to 17

17.43%

16.60%

17.06%

18.84%

    18+

50.93%

54.11%

52.40%

56.11%

         

Gender

       

    Male

47.93%

54.42%

51.02%

60.23%

    Female

46.83%

46.15%

46.53%

44.70%

         

Race/Ethnicity

       

    Hispanic

38.07%

37.65%

37.84%

40.79%

    Non-Hisp., Black

27.70%

43.45%

35.21%

41.19%

    Non-Hisp., All Other Races

51.31%

52.89%

52.02%

55.15%

         

Education1

       

    < High School

38.35%

20.71%

30.85%

40.55%

    High School

43.74%

53.18%

47.65%

55.62%

    > High School

60.99%

62.97%

61.99%

61.34%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.13 Past 30-Day Use of Marijuana, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

5.54%

3.82%

4.74%

5.28%

         

Age Group

       

    12 to 17

9.39%

7.12%

8.37%

7.30%

    18+

5.08%

3.44%

4.32%

5.04%

         

Gender

       

    Male

8.24%

5.66%

7.01%

7.30%

    Female

3.14%

1.99%

2.62%

3.39%

         

Race/Ethnicity

       

    Hispanic

6.04%

1.95%

3.79%

4.48%

    Non-Hisp., Black

4.94%

4.10%

4.54%

6.05%

    Non-Hisp., All Other Races

5.60%

3.96%

4.86%

5.21%

         

Education1

       

    < High School

6.24%

3.44%

5.05%

10.13%

    High School

4.94%

3.16%

4.21%

5.92%

    > High School

4.78%

3.59%

4.18%

2.86%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.14 Past 30-Day Use of Cocaine, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

0.60%

0.53%

0.57%

0.59%

         

Age Group

       

    12 to 17

0.98%

0.26%

0.66%

1.09%

    18+

0.56%

0.56%

0.56%

0.53%

         

Gender

       

    Male

0.51%

0.35%

0.43%

0.61%

    Female

0.68%

0.71%

0.69%

0.56%

         

Race/Ethnicity

       

    Hispanic

1.79%

1.09%

1.40%

0.80%

    Non-Hisp., Black

0.70%

1.39%

1.03%

2.09%

    Non-Hisp., All Other Races

0.50%

0.31%

0.41%

0.30%

         

Education1

       

    < High School

2.19%

0.92%

1.65%

0.87%

    High School

0.54%

0.84%

0.67%

0.89%

    > High School

0.00%

0.31%

0.16%

0.18%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.15 Past 30-Day Use of Any Illicit Drug, by Contingent Questioning Structure

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Single Gate Questions

Multiple Gate Questions

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 3, 4

5, 6, 7, 8

         

Total

6.91%

4.75%

5.91%

5.44%

         

Age Group

       

    12 to 17

13.02%

10.63%

11.95%

7.98%

    18+

6.18%

4.08%

5.21%

5.14%

         

Gender

       

    Male

9.30%

6.89%

8.15%

7.68%

    Female

4.80%

2.62%

3.82%

3.34%

         

Race/Ethnicity

       

    Hispanic

7.30%

3.16%

5.02%

4.60%

    Non-Hisp., Black

6.76%

6.76%

6.76%

6.45%

    Non-Hisp., All Other Races

6.91%

4.54%

5.84%

5.33%

         

Education1

       

    < High School

7.66%

4.42%

6.28%

9.46%

    High School

5.89%

3.97%

5.09%

5.94%

    > High School

5.90%

4.05%

4.97%

3.25%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.1.16 Past 30-Day Use of Cigarettes: Percentage of Inconsistent Respondents

 

Single Gate Questions

Multiple Gate Questions

 
 

Multiple Use Questions Absent
Treatment Versions:
1, 3
(n=110)

Multiple Use Questions Present
Treatment Versions:
2, 4
(n=152)

Multiple Use Questions Absent
Treatment Versions:
5, 7
(n=106)

Multiple Use Questions Present
Treatment Versions:
6, 8
(n=128)

Total ACASI
(n=496)

Type of Inconsistency

Sample

%

Sample

%

Sample

%

Sample

%

Sample

%

Total

2

1.82

12

7.90

6

5.66

14

10.94

34

6.86

                     

"Yes" to Period; 0 Days Reported

2

1.82

5

3.29

6

5.66

14

10.94

27

5.44

                     

"No" to Period; Greater Than 0 Days Reported

N/A

7

4.61

N/A

0

0.00

7

1.41

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.1.17 Past 30-Day Use of Alcohol: Percentage of Inconsistent Respondents

 

Single Gate Questions

Multiple Gate Questions

 
 

Multiple Use Questions Absent
Treatment Versions:
1, 3
(n=171)

Multiple Use Questions Present
Treatment Versions:
2, 4
(n=265)

Multiple Use Questions Absent
Treatment Versions:
5, 7
(n=172)

Multiple Use Questions Present
Treatment Versions:
6, 8
(n=213)

Total ACASI
(n=821)

Type of Inconsistency

Sample

%

Sample

%

Sample

%

Sample

%

Sample

%

Total

11

6.43

25

9.43

19

11.05

26

12.21

81

9.87

                     

"Yes" to Period; 0 Days Reported

11

6.43

14

5.28

19

11.05

13

6.10

57

6.94

                     

"No" to Period; Greater Than 0 Days Reported

N/A

11

4.15

N/A

13

6.10

24

2.92

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.1.18 Past 30-Day Use of Marijuana: Percentage of Inconsistent Respondents

 

Single Gate Questions

Multiple Gate Questions

 
 

Multiple Use Questions Absent
Treatment Versions:
1, 3
(n=49)

Multiple Use Questions Present
Treatment Versions:
2, 4
(n=85)

Multiple Use Questions Absent
Treatment Versions:
5, 7
(n=39)

Multiple Use Questions Present
Treatment Versions:
6, 8
(n=64)

Total ACASI
(n=237)

Type of Inconsistency

Sample

%

Sample

%

Sample

%

Sample

%

Sample

%

Total

1

2.04

9

10.59

6

15.40

7

10.94

23

9.71

                     

"Yes" to Period; 0 Days Reported

1

2.04

0

0.00

6

15.40

3

4.69

10

4.22

                     

"No" to Period; Greater Than 0 Days Reported

N/A

9

10.59

N/A

4

6.25

13

5.49

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.1.19 Past 12-Month Use of Alcohol: Percentage of Inconsistent Respondents

 

Single Gate Questions

Multiple Gate Questions

 
 

Multiple Use Questions Absent
Treatment Versions:
1, 3
(n=0)

Multiple Use Questions Present
Treatment Versions:
2, 4
(n=321)

Multiple Use Questions Absent
Treatment Versions:
5, 7
(n=0)

Multiple Use Questions Present
Treatment Versions:
6, 8
(n=247)

Total ACASI
(n=568)

Type of Inconsistency

Sample

%

Sample

%

Sample

%

Sample

%

Sample

%

Total

N/A

30

9.35

N/A

29

11.74

59

10.39

                     

"Yes" to Period; 0 Days Reported

N/A

18

5.61

N/A

20

8.10

38

6.69

                     

"No" to Period; Greater Than 0 Days Reported

N/A

12

3.74

N/A

9

3.64

21

3.70

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.1.20 Past 12-Month Use of Marijuana: Percentage of Inconsistent Respondents

 

Single Gate Questions

Multiple Gate Questions

 
 

Multiple Use Questions Absent
Treatment Versions:
1, 3
(n=0)

Multiple Use Questions Present
Treatment Versions:
2, 4
(n=110)

Multiple Use Questions Absent
Treatment Versions:
5, 7
(n=0)

Multiple Use Questions Present
Treatment Versions:
6, 8
(n=80)

Total ACASI
(n=190)

Type of Inconsistency

Sample

%

Sample

%

Sample

%

Sample

%

Sample

%

Total

NA

14

12.73

NA

12

15.00

26

13.68

                     

"Yes" to Period; 0 Days Reported

NA

3

2.73

NA

6

7.50

9

4.74

                     

"No" to Period; Greater Than 0 Days Reported

NA

11

10.00

NA

6

7.50

17

8.95

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.1.21 Average Time to Complete Treatment Sections, by Old and New Treatment Versions

 

Single Gate Questions
(Treatment Versions:
1, 2, 3, 4)

Multiple Gate Questions
(Treatment Versions:
5, 6 ,7, 8)

Questionnaire Section

# of Cases

Time
(minutes)

# of Cases

Time
(minutes)

Tobacco

1,068

1.49

909

1.71

Alcohol

1,069

3.20

907

3.36

Marijuana

1,069

0.80

907

1.02

Cocaine

1,069

0.35

907

0.59

Crack

633

0.28

467

0.54

Heroin

1,069

0.19

907

0.39

Hallucinogens

1,068

1.48

907

1.42

Inhalants

1,066

2.44

906

2.41

Total for Treatment Sections

1,071

10.23

911

11.40

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.1.22 Breakoff Rates, by Old and New Treatment Versions

 

Single Gate Questions
Treatment Versions:
1, 2, 3, 4

Multiple Gate Questions
Treatment Versions:
5, 6, 7, 8

Cases Included

n

%

n

%

Cases Ever Recorded as Breakoff Even if Completed Later

89

8.31

74

8.12

         

Cases Finalized as Breakoff

16

1.49

16

1.76

         

Total Number of Respondents Assigned to Treatment Versions

1,071

 

911

 

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.1.23 Respondent Reactions to CAI Interview, by Old and New Treatment Versions

   

Single Gate Questions
(Treatment Versions:
1, 2, 3, 4)

Multiple Gate Questions
(Treatment Versions:
5, 6, 7, 8)

Item

n

%

n

%

How Difficult to Use Computer?

       

    Very difficult

22

2.08

20

2.23

    Somewhat difficult

75

7.10

49

5.47

    Not at all difficult

959

90.81

827

92.30

Total

1,056

100.00

896

100.00

Able to Enter Answers Easily?

       

    Yes

949

89.78

775

86.50

    No

108

10.22

121

13.50

Total

1,057

100.00

896

100.00

Wanted to Change Previous Answer But Did Not?

       

    Yes

195

18.52

162

18.14

    No

858

81.48

731

81.86

Total

1,053

100.00

893

100.00

    Level of interest in interview

       

    Very boring

69

6.58

59

6.61

    Somewhat boring

116

11.06

111

12.44

    Neither boring nor interesting

283

26.98

224

25.11

    Somewhat interesting

364

34.70

305

34.19

    Very interesting

217

20.69

193

21.64

Total

1,049

100.0

892

100.00

Accuracy and Completeness of Answers

       

    Very accurate and complete

872

82.81

748

83.76

    Fairly accurate and complete

171

16.24

133

14.89

    Not very accurate and complete

10

0.95

12

1.34

Total

1,053

100.00

893

100.00

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

7.2 Multiple Opportunities to Report Use

The idea behind allowing respondents more than one opportunity to report drug use was that respondents who were initially unwilling to report more frequent use might change their minds and report the usage in a later question. Respondents who reported use in the past 12 months were given a second opportunity to report use in the past 30 days by being routed to the 30-day frequency question. Respondents who reported use more than 12 months ago (but within the past 3 years) were given the opportunity to report use in the past 12 months by being routed to the 12-month frequency question. Subsequently, respondents who indicated 12-month use were then also routed to the 30-day frequency item. Respondents who reported use more than 3 years ago were not included in any of the multiple use routing schemes.

7.2.1 Prevalence Estimates

Exhibits 7.2.1 through 7.2.15 compare prevalence estimates between the two multiple use treatments for lifetime drug use, past 12-month use, and past 30-day use for cigarettes, alcohol, marijuana, cocaine, and any illicit drug use. In these exhibits, comparable data are included for the 1997 Quarter 4 PAPI data collection. The results do not show a consistent increase in drug use reporting for the inclusion of the multiple questioning approach. For drugs other than tobacco and alcohol, lifetime prevalence increased under the multiple use approach, but for 12-month and 30-day use, many of the drug prevalences appeared to decrease under the multiple questioning approach. Although sample sizes for some of the drugs were quite small and the associated prevalence estimates may be unstable, it seems that the multiple use approach may have introduced random variation (or "noise") into the data rather than reflect any true increase in reporting.

It should be noted, however, that the prevalence estimates in the multiple questioning approach can be manipulated by the rules used to classify the recency of use. Rules must be defined to determine how to classify each respondent based on his or her recency of use. These rules can become quite complex, particularly when combined with the consistency check treatment. In some cases, a respondent may give highly inconsistent answers, and the ensuing prevalence estimates can be generated using either a very conservative or a very liberal (or anywhere in between) classification scheme. A conservative scheme would require a respondent's data to be entirely consistent before his or her data were included in the prevalence analysis. A liberal scheme would allow for a "preponderance of the evidence" rule, which would categorize the respondent based on what the majority of his or her data indicate. For the prevalence exhibits presented here, we have chosen to use a conservative classification scheme so that the prevalence estimates will be somewhat lower than would be obtained with a more liberal classification scheme.

To illustrate how editing rules affect the results, we also created a series of weighted estimates using different editing rules. In Exhibit 7.2.16, we compare theestimates for 30-day use for youths and adults. These exhibits display the estimates using

  1. the raw variables, which make use of the most direct question on use during the 30-day period;

  2. a most liberal editing rule, which counts a person as a 30-day user if he or she gave any indication of use, that is,

    1. provided consistent reports of 30-day use,

    2. indicated that his or her most recent use was in the 30-day period but reported using 0 days in the past 30 days, or

    3. indicated that his or her most recent use was more than 30 days ago but reported using more than 0 days in the past 30 days;

  3. and an approximate NHSDA editing rule, which counted some inconsistent reporters as 30-day users.

Under our edited variables, inconsistent 30-day users were only counted as 30-day users if they had not been consistent in reporting 12-month use.

Examining the results, we note that using liberal editing rules leads to higher reports than using either the conservative editing rules we have used or the rule that is similar to the NHSDA, particularly for those treatments employing multiple use questions. Also, it is interesting to note that the most liberal editing rule tended to track the estimates from the raw variables. This is because the number of people who reported that they used in the past 30 days and who subsequently reported 0 days of use tended to be balanced by the number who said they did not use in the past 30 days and who subsequently reported some days of use.17

7.2.2 Inconsistencies in Reporting

When examining the utility of the multiple questioning approach, it is useful to consider how many respondents reported more recent use as a result of being routed to a question that gave them an opportunity to do so. Exhibit 7.2.17 provides these data in two ways. It was possible that respondents could report more recent use when given a second chance to report, and there was also the possibility that respondents who initially reported 12-month or 30-day use might negate this answer as part of the multiple use questioning. For example, a respondent who reported use of marijuana during the past 12 months would then be routed to the series of questions on frequency of use in the past 12 months. This series of questions includes a response option for "no use during the past 12 months" (because some respondents would be routed to this question after reporting use more than 12 months ago but during the past 3 years). Ifthis respondent then selects the "no use" option, he or she is routed past the 12-month frequency question. So, the multiple use feature has the ability to create more recent users as well as to negate users.

Both cases are observed in Exhibit 7.2.17. The data in this exhibit are quite interesting. A total of 141 respondents gave at least one inconsistent response as a result of the multiple use treatment. Based on an overall sample size of 1,025 respondents assigned to the multiple use treatment, this means approximately 14% of the sample was affected by the multiple use treatment. On average across the four multiple use treatments, approximately two thirds of these respondents indicated more recent use, while a third suggested their use was less recent.

We also examined the inconsistencies in reporting 30-day use for alcohol, cigarettes, marijuana, hallucinogens, and inhalants by determining the proportion of consistent reporters among those who gave any indication of use in the past 30 days. We examined the PAPI data and the analysis was confined to data for the ACASI respondents in the multiple use treatment. There is only a slight indication that the ACASI respondents gave more consistent reports (data not shown in an exhibit). For alcohol, 85% of the respondents who gave any indication of use in the past 30 days were consistent reporters of use in the past 30 days for both the PAPI comparison group and the ACASI multiple use treatment group; for cigarettes, 86% of the PAPI respondents and 89% of the ACASI respondents were consistent reporters. For marijuana, the corresponding figures are 69% for the PAPI respondents and 82% for the ACASI respondents. For hallucinogens, only 37% and 38% of the respondents in PAPI and ACASI, respectively, gave consistent reports. For inhalants, among those who gave any indication of use in the past 30 days, 58% of the PAPI respondents and 43% of the ACASI respondents gave consistent reports.

These large inconsistencies in reporting indicate that more work still needs to be done to increase the saliency of the reference periods for the respondents and to assist them in deciding when an event is in or out of the reference period. For rarely used drugs, some respondents may be reporting the total number of times that they have used the substance, not the number of times in the past 30 days.

7.2.3 Operational Aspects of Reporting Under Multiple Opportunities to Report Use

Time required to complete the interview. Exhibit 7.2.18 provides descriptive data on the average length of time required to complete the treatment section of the 1997 field experiment instrument when the multiple use treatment was and was not in use. Data are included for each individual drug section and for the treatment section as a whole. From this exhibit, we see that the average time to complete each drug section was nearly identical between the two multiple use conditions. The overall average times were identical as well. It appears that the additional questions respondents must answer in the multiple use treatment have little, if any, affect on the overall length of theinterview. More detailed analysis of timing data from the field experiment are presented in Section 7.5.

Breakoff rates. We next compared the rate of incomplete interviews (commonly known as "breakoffs") by analyzing whether the multiple use treatment was in use. Breakoff cases accounted for only a small number of the total number of interviews completed for the 1997 field experiment. However, if the multiple use treatment had caused respondents not to complete the full interview, we would view this as a serious drawback of the methodology. We analyzed the breakoff data in two ways. First, we compared the percentage of cases ever reported as a breakoff (even if the interviewer went on to finalize the case as a completed interview) by multiple use status. Then, we compared the percentage of finalized breakoff cases by multiple use status. Both sets of data are presented in Exhibit 7.2.19. The data show fundamentally that the multiple use treatment had no effect on the breakoff rate for the 1997 field experiment.

Respondent reactions as reported in the debriefing questionnaire. Finally, we analyzed items from the respondent debriefing questions to see whether the multiple use treatment had any effect on respondent reactions to the CAI NHSDA interview. Exhibit 7.2.20 includes data from five items included in the respondent debriefing that we thought might vary by treatment version. Specifically, these items asked respondents to rate their difficulty in using the computer, their interest in the interview, and the accuracy and completeness of their answers. In addition, respondents were asked whether they were able to enter their answers easily and whether they wanted to change an answer to a previous question but did not. The data in Exhibit 7.2.20 show that the multiple use treatment had no effect on respondents' perceptions of the interview as measured by these five items.

Detailed Exhibits for Section 7.2

Exhibit 7.2.1 Lifetime Use of Cigarettes, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

73.87%

69.92%

71.96%

70.87%

         

Age Group

       

    12 to 17

47.37%

41.73%

44.48%

36.05%

    18+

76.77%

73.45%

75.18%

74.94%

         

Gender

       

    Male

77.52%

70.61%

74.25%

74.74%

    Female

70.34%

69.29%

69.83%

67.25%

         

Race/Ethnicity

       

    Hispanic

64.80%

62.62%

63.68%

55.82%

    Non-Hisp., Black

72.83%

54.21%

64.30%

61.62%

    Non-Hisp., All Other Races

74.81%

73.22%

74.04%

73.81%

         

Education1

       

    < High School

79.66%

76.50%

77.83%

70.28%

    High School

78.03%

81.71%

79.73%

76.65%

    > High School

75.27%

66.72%

71.35%

75.27%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.2 Lifetime Use of Alcohol, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

83.53%

82.75%

83.16%

82.15%

         

Age Group

       

    12 to 17

46.93%

42.97%

44.90%

38.01%

    18+

87.53%

87.74%

87.63%

87.31%

         

Gender

       

    Male

84.98%

82.81%

83.95%

87.07%

    Female

82.12%

82.70%

82.41%

77.55%

         

Race/Ethnicity

       

    Hispanic

72.09%

76.34%

74.26%

69.45%

    Non-Hisp., Black

68.01%

62.61%

65.54%

72.35%

    Non-Hisp., All Other Races

87.35%

86.71%

87.04%

84.98%

         

Education1

       

    < High School

81.52%

82.86%

82.30%

77.22%

    High School

86.44%

82.74%

84.73%

85.83%

    > High School

89.65%

92.95%

91.16%

91.48%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.3 Lifetime Use of Marijuana, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

33.38%

37.13%

35.18%

34.96%

         

Age Group

       

    12 to 17

21.79%

19.38%

20.56%

16.10%

    18+

34.64%

39.35%

36.90%

37.17%

         

Gender

       

    Male

36.19%

39.56%

37.78%

40.79%

    Female

30.65%

34.93%

32.75%

29.51%

         

Race/Ethnicity

       

    Hispanic

35.41%

42.55%

39.06%

24.59%

    Non-Hisp., Black

37.18%

23.57%

30.95%

31.43%

    Non-Hisp., All Other Races

32.50%

38.90%

35.60%

36.48%

         

Education1

       

    < High School

25.49%

29.56%

27.85%

32.84%

    High School

35.58%

36.62%

36.06%

36.60%

    > High School

36.14%

44.87%

40.15%

38.91%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.4 Lifetime Use of Cocaine, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

12.11%

17.92%

14.91%

10.03%

         

Age Group

       

    12 to 17

2.74%

2.96%

2.86%

3.13%

    18+

13.13%

19.80%

16.32%

10.84%

         

Gender

       

    Male

13.17%

24.65%

18.60%

12.47%

    Female

11.08%

11.86%

11.46%

7.76%

         

Race/Ethnicity

       

    Hispanic

13.78%

20.67%

17.30%

7.32%

    Non-Hisp., Black

12.79%

6.48%

9.90%

7.57%

    Non-Hisp., All Other Races

11.84%

19.59%

15.59%

10.70%

         

Education1

       

    < High School

14.45%

31.82%

24.51%

9.52%

    High School

16.02%

12.25%

14.27%

10.37%

    > High School

10.91%

20.39%

15.26%

11.58%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.5 Lifetime Use of Any Illicit Drug, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

41.59%

46.00%

43.72%

37.50%

         

Age Group

       

    12 to 17

32.80%

29.59%

31.15%

20.45%

    18+

42.56%

48.06%

45.19%

39.49%

         

Gender

       

    Male

38.83%

49.18%

43.72%

43.44%

    Female

44.27%

43.14%

43.72%

31.94%

         

Race/Ethnicity

       

    Hispanic

39.99%

48.32%

44.25%

28.63%

    Non-Hisp., Black

43.67%

28.22%

36.59%

33.40%

    Non-Hisp., All Other Races

41.34%

48.77%

44.93%

38.99%

         

Education1

       

    < High School

31.64%

54.79%

45.05%

37.22%

    High School

46.50%

44.04%

45.36%

38.42%

    > High School

42.47%

48.25%

45.12%

40.92%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.6 Past 12-Month Use of Cigarettes, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

29.20%

33.32%

31.19%

33.52%

         

Age Group

       

    12 to 17

27.42%

18.55%

22.88%

25.18%

    18+

29.39%

35.17%

32.16%

34.49%

         

Gender

       

    Male

34.81%

37.01%

35.85%

34.17%

    Female

23.77%

30.00%

26.82%

32.91%

         

Race/Ethnicity

       

    Hispanic

34.22%

23.13%

28.55%

32.69%

    Non-Hisp., Black

41.84%

15.85%

29.94%

35.19%

    Non-Hisp., All Other Races

26.44%

37.18%

31.64%

33.29%

         

Education1

       

    < High School

35.70%

52.11%

45.20%

34.76%

    High School

26.67%

46.89%

36.04%

41.55%

    > High School

29.73%

20.88%

25.67%

29.70%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.7 Past 12-Month Use of Alcohol, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

66.16%

70.56%

68.28%

64.95%

         

Age Group

       

    12 to 17

37.68%

35.28%

36.45%

32.74%

    18+

69.27%

74.98%

72.00%

68.71%

         

Gender

       

    Male

63.43%

76.85%

69.78%

70.07%

    Female

68.80%

64.89%

66.88%

60.15%

         

Race/Ethnicity

       

    Hispanic

60.90%

66.28%

63.65%

57.10%

    Non-Hisp., Black

54.92%

44.87%

50.31%

53.54%

    Non-Hisp., All Other Races

68.67%

75.26%

71.86%

67.64%

         

Education1

       

    < High School

35.59%

68.41%

54.60%

48.54%

    High School

70.92%

70.67%

70.80%

68.12%

    > High School

75.98%

80.37%

77.99%

75.47%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.8 Past 12-Month Use of Marijuana, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

9.12%

11.45%

10.24%

9.36%

         

Age Group

       

    12 to 17

17.03%

16.36%

16.69%

12.97%

    18+

8.26%

10.83%

9.49%

8.94%

         

Gender

       

    Male

11.33%

16.77%

13.91%

13.08%

    Female

6.98%

6.65%

6.82%

5.88%

         

Race/Ethnicity

       

    Hispanic

15.05%

12.98%

13.99%

10.21%

    Non-Hisp., Black

8.94%

7.56%

8.31%

9.60%

    Non-Hisp., All Other Races

8.67%

11.96%

10.26%

9.25%

         

Education1

       

    < High School

8.69%

7.58%

8.05%

14.87%

    High School

6.95%

10.50%

8.59%

10.10%

    > High School

9.03%

12.28%

10.52%

6.30%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.9 Past 12-Month Use of Cocaine, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

3.11%

2.12%

2.63%

1.60%

         

Age Group

       

    12 to 17

1.75%

1.79%

1.77%

2.54%

    18+

3.26%

2.16%

2.74%

1.49%

         

Gender

       

    Male

3.17%

2.95%

3.07%

2.10%

    Female

3.06%

1.37%

2.23%

1.13%

         

Race/Ethnicity

       

    Hispanic

4.18%

5.04%

4.62%

1.56%

    Non-Hisp., Black

4.86%

1.67%

3.40%

2.98%

    Non-Hisp., All Other Races

2.70%

1.93%

2.33%

1.36%

         

Education1

       

    < High School

8.90%

2.48%

5.19%

1.87%

    High School

1.51%

2.27%

1.86%

2.03%

    > High School

3.12%

1.97%

2.59%

1.01%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.10 Past 12-Month Use of Any Illicit Drug, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

14.54%

15.82%

15.16%

10.28%

         

Age Group

       

    12 to 17

24.26%

21.87%

23.03%

14.54%

    18+

13.48%

15.06%

14.24%

9.78%

         

Gender

       

    Male

13.08%

19.77%

16.24%

13.87%

    Female

15.96%

12.26%

14.14%

6.93%

         

Race/Ethnicity

       

    Hispanic

20.34%

20.06%

20.20%

12.33%

    Non-Hisp., Black

14.42%

10.76%

12.74%

9.99%

    Non-Hisp., All Other Races

14.09%

16.28%

15.15%

10.16%

         

Education1

       

    < High School

13.76%

9.91%

11.53%

14.57%

    High School

14.73%

12.46%

13.68%

10.63%

    > High School

12.59%

18.75%

15.41%

7.71%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.11 Past 30-Day Use of Cigarettes, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

21.75%

30.98%

26.20%

30.45%

         

Age Group

       

    12 to 17

17.31%

14.98%

16.11%

18.56%

18+

22.23%

32.99%

27.38%

31.84%

         

Gender

       

    Male

23.60%

33.82%

28.43%

31.10%

    Female

19.95%

28.43%

24.11%

29.84%

         

Race/Ethnicity

       

    Hispanic

29.29%

21.55%

25.33%

28.86%

    Non-Hisp., Black

36.76%

10.63%

24.79%

33.03%

    Non-Hisp., All Other Races

18.34%

35.26%

26.53%

30.13%

         

Education1

       

    < High School

33.38%

51.74%

44.01%

34.23%

    High School

22.60%

43.42%

32.25%

38.72%

    > High School

19.41%

18.89%

19.17%

26.50%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.12 Past 30-Day Use of Alcohol, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

50.23%

47.04%

48.70%

52.21%

         

Age Group

       

    12 to 17

18.07%

16.10%

17.06%

18.84%

    18+

53.75%

50.92%

52.40%

56.11%

         

Gender

       

    Male

45.82%

56.81%

51.02%

60.23%

    Female

54.51%

38.24%

46.53%

44.70%

         

Race/Ethnicity

       

    Hispanic

47.53%

28.58%

37.84%

40.79%

    Non-Hisp., Black

40.26%

29.24%

35.21%

41.19%

    Non-Hisp., All Other Races

52.31%

51.72%

52.02%

55.15%

         

Education1

       

    < High School

21.18%

37.88%

30.85%

40.55%

    High School

49.16%

45.90%

47.65%

55.62%

    > High School

64.33%

59.22%

61.99%

61.34%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.13 Past 30-Day Use of Marijuana, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

5.35%

4.09%

4.74%

5.28%

         

Age Group

       

    12 to 17

9.77%

7.03%

8.37%

7.30%

    18+

4.86%

3.72%

4.32%

5.04%

         

Gender

       

    Male

7.42%

6.55%

7.01%

7.30%

    Female

3.34%

1.88%

2.62%

3.39%

         

Race/Ethnicity

       

    Hispanic

2.40%

5.11%

3.79%

4.48%

    Non-Hisp., Black

5.05%

3.93%

4.54%

6.05%

    Non-Hisp., All Other Races

5.65%

4.03%

4.86%

5.21%

         

Education1

       

    < High School

7.07%

3.58%

5.05%

10.13%

    High School

3.83%

4.64%

4.21%

5.92%

    > High School

5.04%

3.16%

4.18%

2.86%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.14 Past 30-Day Use of Cocaine, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

0.56%

0.57%

0.57%

0.59%

         

Age Group

       

    12 to 17

0.21%

1.08%

0.66%

1.09%

    18+

0.60%

0.51%

0.56%

0.53%

         

Gender

       

    Male

0.30%

0.58%

0.43%

0.61%

Female

0.81%

0.57%

0.69%

0.56%

         

Race/Ethnicity

       

    Hispanic

0.68%

2.09%

1.40%

0.80%

    Non-Hisp., Black

0.96%

1.12%

1.03%

2.09%

    Non-Hisp., All Other Races

0.48%

0.34%

0.41%

0.30%

         

Education1

       

    < High School

2.35%

1.14%

1.65%

0.87%

    High School

0.46%

0.91%

0.67%

0.89%

    > High School

0.29%

0.00%

0.16%

0.18%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.15 Past 30-Day Use of Any Illicit Drug, by Opportunities to Report Use

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Multiple Use Questions Absent

Multiple Use Questions Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 3, 5, 7

2, 4, 6, 8

         

Total

6.65%

5.13%

5.91%

5.44%

         

Age Group

       

    12 to 17

13.10%

10.85%

11.95%

7.98%

    18+

5.94%

4.41%

5.21%

5.14%

         

Gender

       

    Male

8.66%

7.58%

8.15%

7.68%

    Female

4.70%

2.91%

3.82%

3.34%

         

Race/Ethnicity

       

    Hispanic

3.64%

6.34%

5.02%

4.60%

    Non-Hisp., Black

7.15%

6.30%

6.76%

6.45%

    Non-Hisp., All Other Races

6.80%

4.82%

5.84%

5.33%

         

Education1

       

    < High School

7.59%

5.33%

6.28%

9.46%

    High School

5.16%

5.01%

5.09%

5.94%

    > High School

6.08%

3.66%

4.97%

3.25%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.2.16 Comparison of 30-Day User Coding Schemes

Drugs of Interest

Single Gate Questions
(Treatment Versions:
1, 2, 3, 4)

Multiple Gate Questions
(Treatment Versions:
5, 6, 7, 8)

PAPI
Comparison

Raw
Variable

Most
Liberal

Approximate
NHSDA

Edited
Variable

Raw
Variable

Most
Liberal

Approximate
NHSDA

Edited
Variable

Alcohol

                 

    Total

50.70%

49.87%

47.64%

47.35%

55.16%

55.78%

51.78%

50.27%

46.45%

    12 to 17

20.78%

21.49%

18.79%

17.43%

21.04%

21.36%

18.70%

16.60%

12.04%

    18+

54.28%

53.26%

51.09%

50.93%

59.05%

59.70%

55.55%

54.11%

50.47%

Cigarettes

                 

    Total

26.19%

26.67%

26.61%

26.61%

27.22%

26.63%

25.73%

25.73%

27.47%

    12 to 17

16.41%

16.92%

16.65%

16.62%

20.30%

16.97%

15.49%

15.49%

12.83%

    18+

27.36%

27.84%

27.80%

27.80%

28.01%

27.73%

26.89%

26.89%

29.19%

Marijuana

                 

    Total

6.18%

6.47%

6.45%

5.54%

4.68%

4.67%

3.92%

3.82%

4.24%

    12 to 17

9.44%

9.85%

9.73%

9.39%

8.63%

8.76%

7.63%

7.12%

5.26%

    18+

5.79%

6.06%

6.06%

5.08%

4.23%

4.20%

3.50%

3.44%

4.12%

Cocaine

                 

    Total

0.61%

0.61%

0.60%

0.60%

0.84%

0.58%

0.53%

0.53%

0.30%

    12 to 17

1.02%

1.02%

0.98%

0.98%

0.64%

0.49%

0.26%

0.26%

0.71%

    18+

0.56%

0.56%

0.56%

0.56%

0.86%

0.59%

0.56%

0.56%

0.26%

Any Illicit Drug1

                 

    Total

 

7.82%

7.79%

6.91%

 

5.62%

4.89%

4.75%

5.44%

    12 to 17

 

14.30%

13.95%

13.02%

 

12.15%

11.52%

10.63%

7.98%

    18+

 

7.05%

7.05%

6.18%

 

4.87%

4.30%

4.08%

5.14%

Alcohol

                 

    Total

52.58%

52.58%

50.23%

50.23%

52.96%

52.61%

48.82%

47.04%

46.45%

    12 to 17

21.50%

21.50%

18.07%

18.07%

20.32%

21.38%

19.40%

16.10%

12.04%

    18+

55.97%

55.97%

53.75%

53.75%

57.05%

56.53%

52.50%

50.92%

50.47%

Cigarettes

                 

    Total

22.52%

22.32%

21.75%

21.75%

31.13%

31.31%

30.99%

30.98%

27.47%

    12 to 17

19.54%

17.82%

17.31%

17.31%

16.84%

16.11%

15.01%

14.98%

12.83%

    18+

22.84%

22.81%

22.23%

22.23%

32.92%

33.21%

32.99%

32.99%

29.19%

Marijuana

                 

    Total

5.97%

5.97%

5.35%

5.35%

4.97%

5.28%

5.22%

4.09%

4.24%

    12 to 17

10.34%

10.34%

9.77%

9.77%

7.87%

8.42%

7.84%

7.03%

5.26%

    18+

5.49%

5.49%

4.86%

4.86%

4.61%

4.89%

4.89%

3.72%

4.12%

Cocaine

                 

    Total

0.56%

0.56%

0.56%

0.56%

0.87%

0.63%

0.57%

0.57%

0.30%

    12 to 17

0.21%

0.21%

0.21%

0.21%

1.46%

1.32%

1.08%

1.08%

0.71%

    18+

0.60%

0.60%

0.60%

0.60%

0.80%

0.54%

0.51%

0.51%

0.26%

Any Illicit Drug 1

                 

    Total

 

7.31%

6.65%

6.65%

 

6.27%

6.24%

5.13%

5.44%

12 to 17

 

14.04%

13.10%

13.10%

 

12.65%

12.62%

10.85%

7.98%

    18+

 

6.57%

5.94%

5.94%

 

5.47%

5.44%

4.41%

5.14%

Alcohol

                 

    Total

51.09%

49.91%

45.37%

44.80%

54.59%

55.55%

54.15%

52.98%

46.45%

    12 to 17

20.30%

20.91%

17.92%

16.16%

21.59%

22.05%

19.72%

18.12%

12.04%

    18+

54.82%

53.42%

48.69%

48.27%

58.30%

59.32%

58.02%

56.91%

50.47%

Cigarettes

                 

    Total

23.13%

22.87%

22.87%

22.87%

30.56%

30.80%

29.86%

29.86%

27.47%

    12 to 17

16.52%

15.50%

15.50%

15.50%

20.08%

18.63%

16.87%

16.83%

12.83%

    18+

23.93%

23.76%

23.76%

23.76%

31.74%

32.17%

31.33%

31.33%

29.19%

Marijuana

                 

    Total

5.10%

4.56%

3.95%

3.74%

5.91%

6.82%

6.75%

5.84%

4.24%

    12 to 17

8.46%

8.70%

8.22%

7.73%

9.80%

10.12%

9.44%

9.11%

5.26%

    18+

4.70%

4.06%

3.43%

3.26%

5.48%

6.45%

6.45%

5.48%

4.12%

Cocaine

                 

    Total

0.70%

0.62%

0.59%

0.59%

0.72%

0.57%

0.54%

0.54%

0.30%

    12 to 17

1.03%

1.03%

1.03%

1.03%

0.64%

0.49%

0.22%

0.22%

0.71%

    18+

0.66%

0.57%

0.54%

0.54%

0.73%

0.57%

0.57%

0.57%

0.26%

Any Illicit Drug 1

                 

    Total

 

5.47%

4.83%

4.66%

 

8.27%

8.23%

7.30%

5.44%

12 to 17

 

12.18%

11.67%

10.44%

 

14.67%

14.26%

13.71%

7.98%

    18+

 

4.66%

4.00%

3.96%

 

7.55%

7.55%

6.58%

5.14%

Note: Raw variable estimates are unavailable for coding schemes for any illicit drug use.

1 Any illicit drug includes marijuana, cocaine, crack, heroin, inhalants, hallucinogens, and nonmedical use of analgesics, sedatives, stimulants, and tranquilizers.

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures, 1997 Field Experiment.

Exhibit 7.2.17 Number of Respondents Who Provided Inconsistent Reports of the Recency of Use as a Result of the Multiple Use Treatment

 

Multiple Use Present

 

Single Gate Question

Multiple Gate Questions

 
 

Consistency Checks

Consistency Checks

 
 

Absent

Present

Absent

Present

 
 

2

4

6

8

Total

Number of Respondents

285

264

219

207

975

           

Total Number of Inconsistencies

48

24

41

28

141

           

Suggests More Recent Use

38

16

22

17

93

           

Percentage of Inconsistencies

79.2

66.7

53.7

60.7

66.0

           

Suggests Less Recent Use

10

8

19

11

48

           

Percentage of Inconsistencies

20.8

33.3

46.3

39.3

34.0

           

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.2.18 Average Time to Complete Treatment Sections, by Whether Multiple Use Was Present

 

Average Time to Complete

 

Multiple Use Present

Multiple Use Absent

Questionnaire Section

# of Cases

Time
(minutes)

# of Cases

Time
(minutes)

Tobacco

1,022

1.6

955

1.6

Alcohol

1,020

3.3

956

3.3

Marijuana

1,020

0.9

956

0.9

Cocaine

1,020

0.5

956

0.5

Crack

1,020

0.4

80

0.6

Heroin

1,020

0.3

956

0.3

Hallucinogens

1,019

1.5

956

1.4

Inhalants

1,019

2.5

953

2.4

Total for Treatment Sections

1,022

10.9

956

10.5

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.2.19 Breakoff Rates, by Multiple Use Status

 

Breakoff Rate

 

Multiple Use Present

Multiple Use Absent

Cases Included

n

%

n

%

Cases Ever Recorded as Breakoff Even if Completed Later

85

8.3

78

8.2

         

Cases Finalized as Breakoff

17

1.7

15

1.6

         

Total Number of Respondents Assigned to Multiple Use Treatment

1,025

 

957

 

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.2.20 Respondent Reactions to CAI Interview, by Multiple Use Status

 

Multiple Use Status

 

Multiple Use Present

Multiple Use Absent

Item

n

%

n

%

How Difficult to Use Computer?

       

      Very difficult

23

2.3

19

2.0

      Somewhat difficult

63

6.2

61

6.5

      Not at all difficult

923

91.5

863

91.5

Total

1,009

100.0

943

100.0

Able to Enter Answers Easily?

       

      Yes

891

88.2

833

88.3

      No

119

11.8

110

11.7

Total

1,010

100.0

943

100.0

Wanted to Change Previous Answer But Did Not?

       

      Yes

183

18.2

174

18.5

      No

821

81.8

768

81.5

Total

1,004

100.0

942

100.0

Level of Interest in Interview

       

      Very boring

62

6.2

66

7.0

      Somewhat boring

120

12.0

107

11.4

      Neither boring nor interesting

259

25.8

248

26.4

      Somewhat interesting

350

34.9

319

34.0

      Very interesting

211

21.1

199

21.2

Total

1,003

100.0

939

100.0

Accuracy and Completeness of Answers

       

      Very accurate and complete

831

82.6

789

83.9

      Fairly accurate and complete

163

16.2

141

15.0

      Not very accurate and complete

12

1.2

10

1.1

Total

1,006

100.0

940

100.0

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

7.3 Implementation of Consistency Checks by Respondents

The consistency checks programmed for the consistency check treatment can be divided into two types. First, there are true inconsistencies, in which a respondent's answers to each of two questions cannot both be true. For example, a respondent who has reported her current age as 22 cannot logically report her first use of marijuana at age 35. Similarly, a respondent who reports drinking alcohol on 22 days during the past 30 days cannot logically report drinking alcohol on 3 days in the past 12 months. A second type of check that was programmed can be considered a verify check as opposed to a true inconsistency. In these cases, a respondent's answer is not technically inconsistent with previous information reported but rather is simply "unusual" given what we have learned from the data collected in previous NHSDAs. The two verify checks included in the 1997 field experiment prompted respondents to verify the accuracy of their response when they indicated an age at first use as equal to their current age or an age at first use less than 10. When discussing the outcome of the consistency check treatment, we first must consider the two types of consistency checks separately because they may reflect different effects on data quality.

7.3.1 Inconsistencies in the Final Unedited Respondent Data, by Presence or Absence of Consistency Checks

Exhibit 7.3.1 shows the number of respondents in each of the four versions in which consistency checks were present who triggered at least one consistency check during the course of the interview. From this exhibit, we see that approximately 28% of the respondents assigned to receive consistency checks triggered at least one check item. Of those respondents, just over half (55%) triggered a verify check as opposed to a true inconsistency item. More respondents triggered a true consistency check in Treatments 4 and 8. This may be the result of additional confusion created by the multiple use treatment. However, it may only reflect the fact that there were more consistency checks programmed into these two treatments. Interestingly, the number of respondents who triggered verify items was higher for the two treatments that used the single gate question.

Exhibit 7.3.2 shows a breakdown of the age of respondents who triggered at least one true inconsistency. Across all treatments, youths aged 12 to 17 were more likely to trigger a true inconsistency than adults aged 18 or older. In Treatment 8, the difference was especially pronounced: 23% of youths triggered an inconsistency and only 11.7% of adults did.

In addition to determining the number of respondents who triggered any of the inconsistency items, we also wanted to calculate the total number of consistency checks triggered overall and by treatment. Exhibit 7.3.3 shows these data. Combining these data with data from Exhibit 7.3.1 shows that the average number of true consistency checks triggered was approximately 1.2 per respondent. The average number of verify checks triggered was approximately 1.2 per respondent as well.

Of particular interest is whether the data coming out of the consistency checks were "cleaner" than the data going in. For the 1997 field experiment, we decided to route respondents through each consistency check only once. Thus, if a respondent reported her current age as 26 and her age at first use of cocaine as age 33, she was routed into a consistency check. If she chose to change her age at first use response to 30, her answers would still be inconsistent. However, the program was not designed to route respondents back through a consistency check a second time. We were concerned that multiple passes through a single consistency check might be overly burdensome to respondents.

Exhibit 7.3.4 provides data on the consistency of responses following a consistency check. Each resolution process was examined and classified into one of four types. First, the data could be classified as consistent; that is, after being notified of the inconsistency, the respondent revised one or both of his or her answers so that the answers did not conflict with each other. Second, the data could remain inconsistent; even after changing one or both of the answers, the respondent's answers still conflicted with one another. Some responses were classified as "indeterminate" because the nature of the resolution process did not require the respondent to fully resolve the inconsistency. For example, in Treatment 8, a respondent may have reported that he used marijuana during the past 30 days; when asked the 30-day frequency item, however, he reported 0 days. He was then routed to a resolution screen that asked him to verify that he did not use marijuana in the past 30 days. If he indicated this was correct, that was the end of the resolution process, even though he was never presented with the two conflicting items. Although it seems safe to consider this respondent a nonuser for the 30-day period, for the sake of clarity we have classified these cases separately in Exhibit 7.3.4. Finally, in a small number of situations, the respondent recorded a "don't know" or "refused" response when presented with the resolution screen. In these situations, the program routed the respondent out of the resolution series; thus, the case cannot be classified into any of the other three categories.

From Exhibit 7.3.4, we see that 30% of all inconsistencies were resolved as consistent, 17% were still inconsistent after the resolution process, and just over half (51%) the respondent confirmed an answer. If we assume that the confirmed answer is accurate, then the quality of 81% of the inconsistent responses was improved through the resolution process. Also from Exhibit 7.3.4, we find that slightly less than half of the inconsistencies resolved in Treatments 3 and 4 were determined to be consistent. In contrast, less than 20% of the inconsistencies resolved in Treatments 7 and 8 were determined to be consistent. The reason for this difference is not clear because the resolution questions do not vary significantly between the two contingent questioning structures.

We hypothesized that respondents who were overly confused by the resolution process would enter a "don't know" or "refused" response as a method of avoiding the resolution task. We found only a small number of inconsistencies were "resolved" bythe respondent in this manner (a total of four resolutions across all treatment versions). We take this as a positive sign that the resolution process was not overly confusing for respondents and believe that, overall, the improvement in data consistency is an improvement to the overall quality of the NHSDA data as well.

We also examined the resolution of the verify questions on age at first use in more detail. The results of this analysis are shown in Exhibit 7.3.5, which displays the number of respondents for the various drugs who reported very low ages at first use and the percentage who changed their answers as a result of the consistency check. Overall, 98 respondents gave ages at first use younger than 10 years old, and about 23% of these respondents indicated that this was an incorrect answer. Most of these respondents gave a new age that was consistent; however, a few did not complete the task, and we were left with the knowledge only that they had indicated that the very low age at first use was incorrect.

Exhibit 7.3.5 also shows data on those whose reported age at first use was equal to their current age. The vast majority of these respondents confirmed that this was indeed their age at first use; however, about 6% gave a revised age at first use.

7.3.2 Effect of Revised Answers on Prevalence Estimates

Based on the data presented in Section 7.3.1, it appears that the consistency check process is helpful in improving the consistency of the NHSDA data. In addition, the process seems relatively burden-free because less than a third of the respondents actually triggered a resolution screen and the average number of resolution screens triggered was quite low (1.2 for both the verify and the true inconsistency screens). Of equal importance, however, is the effect of the inconsistency resolution process on the prevalence estimates.

Exhibits 7.3.6 through 7.3.20 compare prevalence estimates between the two levels of the consistency check treatment. In these exhibits, comparable data are included for the 1997 Quarter 4 PAPI data collection. The results show a fairly consistent increase in the drug prevalence rates for both lifetime and 12-month use. The 30-day rates are less consistent, but due to the small sample sizes for many of the drugs, these rates are also likely to be less reliable.

The resolution process appears to have had a slight decreasing effect on the reports of youths aged 12 to 17, while the prevalence rates for adults aged 18 or older were increased by the presence of the resolution treatment. A large increase in the prevalence rates was also found for adults with less than a high school education when the consistency check treatment was included.

7.3.3 Operational Aspects of Reporting When Consistency Checks Are Used

Time required to complete the interview. Exhibit 7.3.21 provides descriptive dataon the average length of time required to complete the treatment section of the instrument when consistency checks were and were not in use. Data are included for each individual drug section and for the treatment section as a whole. From this exhibit, we see that the average time to complete each drug section was nearly identical between the two resolution conditions. The overall average times were identical as well. However, the majority of respondents did not trigger many, if any, consistency checks during their interviews. To present a more realistic picture of the time added by the inclusion of resolution items, we compared the time to complete the treatment section by whether even one inconsistency was resolved during the respondent's interview. The results are presented in Exhibit 7.3.22. Here we see an increase of approximately 3 minutes when at least one consistency check was triggered compared to when none was triggered. One additional method for considering the time added when the consistency checks were present is to compare the time to complete a specific section of the instrument by whether an inconsistency was detected in that section. These data are presented in Exhibit 7.3.23. In some cases, sample sizes are quite small. However, we see that for many of the drug sections, triggering a consistency check could result in a doubling of the time to complete the section compared to when no consistency checks were triggered. More detailed analysis of the timing data from the 1997 field experiment are presented in Section 7.5.

Breakoff rates. We next compared the rate of breakoffs by analyzing whether the multiple use treatment was in use. Breakoff cases accounted for only a small number of the total number of interviews. However, if the consistency checks had caused respondents not to complete the full interview, we would view this as a serious drawback of the methodology. We analyzed the breakoff data in two ways. First, we compared the percentage of cases ever reported as a breakoff (even if the interviewer went on to finalize the case as a completed interview) by the presence of consistency checks. Then, we compared the percentage of finalized breakoff cases. Both sets of data are presented in Exhibit 7.3.24. The data show fundamentally that the presence of consistency checks had no effect on the breakoff rate.

Respondent reactions as reported in the debriefing questionnaire. We analyzed items from the respondent debriefing questions to see whether the consistency checks had any effect on respondent reactions to the CAI NHSDA interview. Exhibit 7.3.25 includes data from five items included in the respondent debriefing that we thought might vary by treatment version. Specifically, these items asked respondents to rate their difficulty in using the computer, their interest in the interview, and the accuracy and completeness of their answers. In addition, respondents were asked whether they were able to enter their answers easily and whether they wanted to change an answer to a previous question but did not. The data in Exhibit 6.3.51 show that respondents in the consistency check present group were slightly more likely than respondents who did not resolve inconsistencies to report that they were able to easily enter their answers into the computer (90.0% vs. 86.6%) and that the answers they gave were very accurate and complete (84.4% vs. 82.1%). For the other items included in Exhibit 7.3.25, no differences were found between the twogroups.

Interviewer reports of respondent difficulties. Interviewers completed debriefing questions at the conclusion of each interview. For respondents who triggered at least one inconsistency item (a true inconsistency rather than only a verify item), one of these debriefing items asked the interviewer to explain why the respondent might have provided inconsistent data. A review of the open-ended responses indicates that the most common reason provided by the interviewers was the number of distractions during the interview. These distractions included the presence of young children, the presence of other adults, the telephone ringing, the doorbell ringing, and the television playing. Other explanations mentioned by the interviewers included respondent boredom, literacy problems, respondent fatigue, and respondents who simply were not paying close attention to what they were doing.

Exhibit 7.3.26 includes data from several other interviewer debriefing items that we thought might differ based on whether the respondent was assigned to receive consistency checks. For the most part, interviewer reports were similar across the two modes. However, interviewers reported that slightly more respondents in the consistency check present group had no difficulty understanding the interview (84.4% vs. 81.4%) and were very interested in the ACASI interview (62.7% vs. 59.9%). Interviewers also reported that for slightly more of the respondents who did not receive the consistency checks, the audio component of ACASI was unnecessary (36.8% vs. 34.5%).

Detailed Exhibits for Section 7.3

Exhibit 7.3.1 Number and Percentage of Respondents Who Triggered at Least One Consistency Check

 

Consistency Checks Present

 

Single Gate Question

Multiple Gate Questions

 
 

Multiple Use Questions

Multiple Use Questions

 
 

Absent

Present

Absent

Present

 

Treatment Version

3

4

7

8

Total

           

Number of Respondents

285

264

219

207

975

           

Total Number of Respondents Who Triggered a Consistency Check

75

82

52

68

277

    Percentage of Respondents

26.3

31.1

23.7

32.9

28.4

           

True Inconsistency

27

39

21

37

124

    Percentage of Respondents

9.5

14.8

9.6

17.9

12.7

    Percentage of Consistency Checks

36.0

47.6

40.3

54.4

44.8

           

Verify Only

48

43

31

31

153

    Percentage of Respondents

16.8

16.3

14.2

15.0

15.7

    Percentage of Consistency Checks

64.0

52.4

59.6

45.6

55.2

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.2 Number of Respondents Who Triggered at Least One True Inconsistency, by Age and Treatment

 

Consistency Checks Present

 

Single Gate Question

Multiple Gate Questions

 
 

Multiple Use Questions

Multiple Use Questions

 
 

Absent

Present

Absent

Present

 

Treatment Version

3

4

7

8

Total

           

Number of Respondents

285

264

219

207

975

           

Total Number of True Inconsistencies Triggered

27

39

21

37

124

    Percentage of Respondents

9.5

14.8

9.6

17.9

12.7

           

12 to 17

         

    Number of Respondents

157

148

118

113

536

    Number Triggering True Inconsistencies

16

22

11

26

75

    Percentage of Respondents

10.2

14.9

9.3

23.0

14.0

           

18+

         

    Number of Respondents

128

116

101

94

439

    Number Triggering True Inconsistencies

11

17

10

11

49

    Percentage of Respondents

8.6

14.7

9.9

11.7

11.2

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.3 Number of Consistency Checks Triggered, by Treatment

 

Consistency Checks Present

 

Single Gate Question

Multiple Gate Questions

 
 

Multiple Use Questions

Multiple Use Questions

 
 

Absent

Present

Absent

Present

 

Treatment Version

3

4

7

8

Total

           

Number of Respondents

285

264

219

207

975

           

Total Number of Consistency Checks Triggered

95

101

60

83

339

           

True Inconsistency

31

50

24

45

150

           

Verify Only

64

51

36

38

189

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.4 Data Consistency Following the Resolution Process

 

Consistency Checks Present

 

Single Gate Question

Multiple Gate Questions

 
 

Multiple Use Questions

Multiple Use Questions

 
 

Absent

Present

Absent

Present

 

Treatment Version

3

4

7

8

Total

Number of Respondents

285

264

219

207

975

           

Total Number of True Inconsistencies Triggered

31

50

24

45

150

           

Made Change: Data Consistent

15

21

4

5

45

    Percentage of inconsistencies

48.4

42.0

16.7

11.1

30.0

           

Made Change: Data Inconsistent

5

6

7

7

25

    Percentage of inconsistencies

16.1

12.0

29.1

15.6

16.7

           

Confirmed Last Answer

8

23

13

32

76

    Percentage of inconsistencies

25.8

46.0

54.2

71.1

50.7

           

Don't Know/Refused

3

0

0

1

4

    Percentage of inconsistencies

9.7

-

-

2.2

2.7

Source: National Household Survey on Drug Abuse: Development of Computer Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.5 Summary of Consistency Resolution for Checks on Age at First Use

Drug

Very Low Age at First Use Reported

Very Low Age at First Use Changed

Reported Age
at First Use Equals Current Age

Current Age
Not Verified as Age of First
Use

Cigarettes

       

    Number

30

7

17

3

    Percentage

 

23.33

 

17.65

Alcohol

       

    Number

50

7

29

0

    Percentage

 

14.00

 

0.00

Marijuana

       

    Number

4

1

18

0

    Percentage

 

25.00

 

0.00

Cocaine

       

    Number

1

1

5

0

    Percentage

 

100.00

 

0.00

Crack

       

    Number

1

0

2

0

    Percentage

 

0.00

 

0.00

Heroin

       

    Number

2

1

2

0

    Percentage

 

50.00

 

0.00

Hallucinogens

       

    Number

3

2

11

1

    Percentage

 

66.67

 

9.09

Inhalants

       

    Number

7

4

4

1

    Percentage

 

57.14

 

25.00

Overall Drugs

       

    Number

98

23

88

5

    Percentage

 

23.47

 

5.68

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.6 Lifetime Use of Cigarettes, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

69.70%

74.45%

71.96%

70.87%

         

Age Group

       

    12 to 17

45.49%

43.29%

44.48%

36.05%

    18+

72.63%

77.96%

75.18%

74.94%

         

Gender

       

    Male

75.47%

72.81%

74.25%

74.74%

    Female

63.97%

75.88%

69.83%

67.25%

         

Race/Ethnicity

       

    Hispanic

61.10%

66.72%

63.68%

55.82%

    Non-Hisp., Black

63.99%

64.56%

64.30%

61.62%

    Non-Hisp., All Other Races

71.32%

77.15%

74.04%

73.81%

         

Education1

       

    < High School

69.58%

87.21%

77.83%

70.28%

    High School

74.28%

86.76%

79.73%

76.65%

    > High School

72.36%

70.37%

71.35%

75.27%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.7 Lifetime Use of Alcohol, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

82.12%

84.30%

83.16%

82.15%

         

Age Group

       

    12 to 17

45.55%

44.14%

44.90%

38.01%

    18+

86.54%

88.82%

87.63%

87.31%

         

Gender

       

    Male

80.29%

88.26%

83.95%

87.07%

    Female

83.94%

80.83%

82.41%

77.55%

         

Race/Ethnicity

       

    Hispanic

76.29%

71.87%

74.26%

69.45%

    Non-Hisp., Black

61.36%

69.05%

65.54%

72.35%

    Non-Hisp., All Other Races

85.77%

88.50%

87.04%

84.98%

         

Education1

       

    < High School

82.62%

81.94%

82.30%

77.22%

    High School

82.80%

87.21%

84.73%

85.83%

    > High School

90.68%

91.63%

91.16%

91.48%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.8 Lifetime Use of Marijuana, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

35.04%

35.34%

35.18%

34.96%

         

Age Group

       

    12 to 17

20.73%

20.36%

20.56%

16.10%

    18+

36.78%

37.02%

36.90%

37.17%

         

Gender

       

    Male

37.89%

37.66%

37.78%

40.79%

    Female

32.22%

33.30%

32.75%

29.51%

         

Race/Ethnicity

       

    Hispanic

49.07%

27.31%

39.06%

24.59%

    Non-Hisp., Black

26.19%

34.95%

30.95%

31.43%

    Non-Hisp., All Other Races

35.15%

36.10%

35.60%

36.48%

         

Education1

       

    < High School

30.04%

25.36%

27.85%

32.84%

    High School

35.73%

36.49%

36.06%

36.60%

    > High School

39.76%

40.52%

40.15%

38.91%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.9 Lifetime Use of Cocaine, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

11.61%

18.54%

14.91%

10.03%

         

Age Group

       

    12 to 17

2.46%

3.32%

2.86%

3.13%

    18+

12.72%

20.25%

16.32%

10.84%

         

Gender

       

    Male

13.36%

24.76%

18.60%

12.47%

    Female

9.88%

13.10%

11.46%

7.76%

         

Race/Ethnicity

       

    Hispanic

25.35%

7.86%

17.30%

7.32%

    Non-Hisp., Black

5.46%

13.65%

9.90%

7.57%

    Non-Hisp., All Other Races

11.34%

20.46%

15.59%

10.70%

         

Education1

       

    < High School

16.48%

33.64%

24.51%

9.52%

    High School

12.61%

16.41%

14.27%

10.37%

    > High School

11.59%

18.79%

15.26%

11.58%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.10 Lifetime Use of Any Illicit Drug, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

43.43%

44.03%

43.72%

37.50%

         

Age Group

       

    12 to 17

30.82%

31.55%

31.15%

20.45%

    18+

44.96%

45.44%

45.19%

39.49%

         

Gender

       

    Male

40.18%

47.88%

43.72%

43.44%

    Female

46.66%

40.67%

43.72%

31.94%

         

Race/Ethnicity

       

    Hispanic

51.88%

35.29%

44.25%

28.63%

    Non-Hisp., Black

28.87%

43.09%

36.59%

33.40%

    Non-Hisp., All Other Races

44.90%

44.98%

44.93%

38.99%

         

Education1

       

    < High School

36.28%

55.02%

45.05%

37.22%

    High School

50.83%

38.32%

45.36%

38.42%

    > High School

43.27%

46.91%

45.12%

40.92%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.11 Past 12-Month Use of Cigarettes, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

28.56%

34.07%

31.19%

33.52%

         

Age Group

       

    12 to 17

23.82%

21.77%

22.88%

25.18%

    18+

29.13%

35.46%

32.16%

34.49%

         

Gender

       

    Male

37.26%

34.20%

35.85%

34.17%

    Female

19.92%

33.96%

26.82%

32.91%

         

Race/Ethnicity

       

    Hispanic

23.36%

34.64%

28.55%

32.69%

    Non-Hisp., Black

23.36%

35.48%

29.94%

35.19%

    Non-Hisp., All Other Races

29.80%

33.73%

31.64%

33.29%

         

Education1

       

    < High School

34.32%

57.58%

45.20%

34.76%

    High School

32.47%

40.65%

36.04%

41.55%

    > High School

24.90%

26.42%

25.67%

29.70%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.12 Past 12-Month Use of Alcohol, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

65.09%

71.79%

68.28%

64.95%

         

Age Group

       

    12 to 17

36.99%

35.83%

36.45%

32.74%

    18+

68.49%

75.83%

72.00%

68.71%

         

Gender

       

    Male

65.13%

75.23%

69.78%

70.07%

    Female

65.05%

68.77%

66.88%

60.15%

         

Race/Ethnicity

       

    Hispanic

65.08%

61.97%

63.65%

57.10%

    Non-Hisp., Black

45.75%

54.16%

50.31%

53.54%

    Non-Hisp., All Other Races

68.02%

76.26%

71.86%

67.64%

         

Education1

       

    < High School

51.86%

57.71%

54.60%

48.54%

    High School

67.24%

75.38%

70.80%

68.12%

    > High School

74.81%

81.06%

77.99%

75.47%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.13 Past 12-Month Use of Marijuana, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

9.95%

10.56%

10.24%

9.36%

         

Age Group

       

    12 to 17

16.17%

17.29%

16.69%

12.97%

    18+

9.20%

9.80%

9.49%

8.94%

         

Gender

       

    Male

13.43%

14.46%

13.91%

13.08%

    Female

6.50%

7.15%

6.82%

5.88%

         

Race/Ethnicity

       

    Hispanic

20.85%

5.95%

13.99%

10.21%

    Non-Hisp., Black

7.41%

9.06%

8.31%

9.60%

    Non-Hisp., All Other Races

9.38%

11.27%

10.26%

9.25%

         

Education1

       

    < High School

9.98%

5.85%

8.05%

14.87%

    High School

8.81%

8.31%

8.59%

10.10%

    > High School

9.25%

11.75%

10.52%

6.30%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.14 Past 12-Month Use of Cocaine, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

2.28%

3.03%

2.63%

1.60%

         

Age Group

       

    12 to 17

1.74%

1.81%

1.77%

2.54%

    18+

2.34%

3.17%

2.74%

1.49%

         

Gender

       

    Male

2.42%

3.82%

3.07%

2.10%

    Female

2.13%

2.34%

2.23%

1.13%

         

Race/Ethnicity

       

    Hispanic

5.52%

3.56%

4.62%

1.56%

    Non-Hisp., Black

1.48%

5.02%

3.40%

2.98%

    Non-Hisp., All Other Races

2.11%

2.57%

2.33%

1.36%

         

Education1

       

    < High School

5.07%

5.32%

5.19%

1.87%

    High School

1.72%

2.04%

1.86%

2.03%

    > High School

1.94%

3.22%

2.59%

1.01%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

.

Exhibit 7.3.15 Past 12-Month Use of Any Illicit Drug, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

14.57%

15.81%

15.16%

10.28%

         

Age Group

       

    12 to 17

21.22%

25.17%

23.03%

14.54%

    18+

13.76%

14.75%

14.24%

9.78%

         

Gender

       

    Male

16.05%

16.47%

16.24%

13.87%

    Female

13.09%

15.23%

14.14%

6.93%

         

Race/Ethnicity

       

    Hispanic

23.93%

15.81%

20.20%

12.33%

    Non-Hisp., Black

9.95%

15.10%

12.74%

9.99%

    Non-Hisp., All Other Races

14.45%

15.95%

15.15%

10.16%

         

Education1

       

    < High School

11.77%

11.27%

11.53%

14.57%

    High School

15.46%

11.39%

13.68%

10.63%

    > High School

13.11%

17.64%

15.41%

7.71%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

.

Exhibit 7.3.16 Past 30-Day Use of Cigarettes, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

22.87%

29.86%

26.20%

30.45%

         

Age Group

       

    12 to 17

15.50%

16.83%

16.11%

18.56%

    18+

23.76%

31.33%

27.38%

31.84%

         

Gender

       

    Male

27.94%

29.02%

28.43%

31.10%

    Female

17.84%

30.60%

24.11%

29.84%

         

Race/Ethnicity

       

    Hispanic

20.83%

30.62%

25.33%

28.86%

    Non-Hisp., Black

17.91%

30.58%

24.79%

33.03%

    Non-Hisp., All Other Races

23.80%

29.64%

26.53%

30.13%

         

Education1

       

    < High School

33.42%

56.06%

44.01%

34.23%

    High School

28.48%

37.10%

32.25%

38.72%

    > High School

17.03%

21.24%

19.17%

26.50%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.17 Past 30-Day Use of Alcohol, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

44.80%

52.98%

48.70%

52.21%

         

Age Group

       

    12 to 17

16.16%

18.12%

17.06%

18.84%

    18+

48.27%

56.91%

52.40%

56.11%

         

Gender

       

    Male

45.13%

57.93%

51.02%

60.23%

    Female

44.47%

48.65%

46.53%

44.70%

         

Race/Ethnicity

       

    Hispanic

39.24%

36.19%

37.84%

40.79%

    Non-Hisp., Black

29.91%

39.68%

35.21%

41.19%

    Non-Hisp., All Other Races

47.54%

57.16%

52.02%

55.15%

         

Education1

       

    < High School

20.37%

42.78%

30.85%

40.55%

    High School

47.46%

47.90%

47.65%

55.62%

    > High School

57.89%

65.95%

61.99%

61.34%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.18 Past 30-Day Use of Marijuana, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

3.74%

5.84%

4.74%

5.28%

         

Age Group

       

    12 to 17

7.73%

9.11%

8.37%

7.30%

18+

3.26%

5.48%

4.32%

5.04%

         

Gender

       

    Male

4.89%

9.49%

7.01%

7.30%

    Female

2.60%

2.65%

2.62%

3.39%

         

Race/Ethnicity

       

    Hispanic

3.82%

3.75%

3.79%

4.48%

    Non-Hisp., Black

3.61%

5.32%

4.54%

6.05%

    Non-Hisp., All Other Races

3.75%

6.13%

4.86%

5.21%

         

Education1

       

    < High School

6.06%

3.89%

5.05%

10.13%

    High School

4.68%

3.59%

4.21%

5.92%

    > High School

1.26%

6.99%

4.18%

2.86%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

.

Exhibit 7.3.19 Past 30-Day Use of Cocaine, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

0.59%

0.54%

0.57%

0.59%

         

Age Group

       

    12 to 17

1.03%

0.22%

0.66%

1.09%

    18+

0.54%

0.57%

0.56%

0.53%

         

Gender

       

    Male

0.32%

0.57%

0.43%

0.61%

    Female

0.87%

0.51%

0.69%

0.56%

         

Race/Ethnicity

       

    Hispanic

1.30%

1.53%

1.40%

0.80%

    Non-Hisp., Black

0.70%

1.30%

1.03%

2.09%

    Non-Hisp., All Other Races

0.52%

0.30%

0.41%

0.30%

         

Education1

       

    < High School

2.09%

1.15%

1.65%

0.87%

    High School

0.59%

0.76%

0.67%

0.89%

    > High School

0.00%

0.31%

0.16%

0.18%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.20 Past 30-Day Use of Any Illicit Drug, by Presence of Consistency Checks

Respondent Characteristics

ACASI Treatment Groups

Comparison Group

Consistency Checks Absent

Consistency Checks Present

Total ACASI

1997
Quarter 4
PAPI/SAQ

Treatment Version:

1, 2, 5, 6

3, 4, 7, 8

         

Total

4.66%

7.30%

5.91%

5.44%

         

Age Group

       

    12 to 17

10.44%

13.71%

11.95%

7.98%

    18+

3.96%

6.58%

5.21%

5.14%

         

Gender

       

    Male

5.89%

10.80%

8.15%

7.68%

    Female

3.43%

4.23%

3.82%

3.34%

         

Race/Ethnicity

       

    Hispanic

4.87%

5.19%

5.02%

4.60%

    Non-Hisp., Black

5.08%

8.17%

6.76%

6.45%

    Non-Hisp., All Other Races

4.57%

7.30%

5.84%

5.33%

         

Education1

       

    < High School

7.29%

5.13%

6.28%

9.46%

    High School

4.84%

5.42%

5.09%

5.94%

    > High School

2.20%

7.64%

4.97%

3.25%

1Education includes only individuals aged 18 or older.

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment. 1997 National Household Survey on Drug Abuse: Quarter 4.

Exhibit 7.3.21 Average Time to Complete Treatment Sections, by Whether Consistency Checks Are Used

 

Average Time to Complete

 

Consistency Check Present

Consistency Check Absent

Questionnaire Section

n

Time
(minutes)

n

Time
(minutes)

Tobacco

972

1.6

1,005

1.6

Alcohol

972

3.4

1,004

3.2

Marijuana

972

0.9

1,004

0.9

Cocaine

972

0.5

1,004

0.5

Crack

515

0.4

585

0.4

Heroin

972

0.3

1,004

0.3

Hallucinogens

971

1.4

1,004

1.5

Inhalants

969

2.4

1,003

2.4

Total for Treatment Section

973

10.8

1,005

10.6

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.22 Average Time to Complete Treatment Sections, by Whether Any Consistency Checks Were Triggered Anywhere in Instrument

 

Average Time to Complete

 

Consistency Check Triggered

No Consistency Check Triggered

Questionnaire Section

n

Time
(minutes)

n

Time
(minutes)

Tobacco

227

2.2

745

1.5

Alcohol

228

4.4

744

3.1

Marijuana

228

1.2

744

0.8

Cocaine

228

0.6

744

0.4

Crack

145

0.4

370

0.4

Heroin

228

0.3

744

0.3

Hallucinogens

228

1.5

743

1.4

Inhalants

227

2.5

742

2.4

Total for Treatment Section

228

13.0

745

10.1

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.23 Average Time to Complete Treatment Sections, by Whether Consistency Checks Were Triggered in Each Particular Section

 

Average Time to Complete

 

Consistency Check Triggered

No Consistency Check Triggered

Questionnaire Section

n

Time
(minutes)

n

Time
(minutes)

Tobacco

68

3.2

904

1.5

Alcohol

137

4.8

835

3.1

Marijuana

33

2.4

939

0.9

Cocaine

9

2.0

963

0.4

Crack

4

1.5

511

0.4

Heroin

4

1.6

968

0.3

Hallucinogens

19

2.9

952

1.4

Inhalants

19

4.3

950

2.4

Total for Treatment Section

228

13.0

745

10.1

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.24 Breakoff Rates, by Consistency Check Status

 

Breakoff Rate

 

Consistency Check Present

Consistency Check Absent

Cases Included

n

%

n

%

Cases Ever Recorded as Breakoff Even if Completed Later

77

7.9

86

8.5

         

Cases Finalized as Breakoff

16

1.6

16

1.6

         

Total Number of Respondents Assigned to Group Treatment

975

 

1,007

 

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.25 Respondent Reactions to CAI Interview, by Consistency Check Status

 

Consistency Check Present

Consistency Check Absent

Item

%

n

%

n

How Difficult to Use Computer?

       

      Very difficult

2.0

19

2.3

23

      Somewhat difficult

6.4

61

6.3

63

      Not at all difficult

91.6

879

91.4

907

Total

100.0

959

100.0

993

Able to Enter Answers Easily?

       

      Yes

90.0

864

86.6

860

      No

10.0

96

13.4

133

Total

100.0

960

100.0

993

Wanted to Change Previous Answer But Did Not?

       

      Yes

18.2

174

18.5

183

      No

81.8

783

81.5

806

Total

100.0

957

100.0

989

Level of Interest in Interview

       

      Very boring

6.2

59

7.0

69

      Somewhat boring

10.2

97

13.2

130

      Neither boring nor interesting

28.2

269

24.1

238

      Somewhat interesting

34.5

329

34.4

340

      Very interesting

20.9

200

21.3

210

Total

100.0

954

100.0

987

Accuracy and Completeness of Answers

       

      Very accurate and complete

84.4

807

82.1

813

      Fairly accurate and complete

14.9

142

16.4

162

      Not very accurate and complete

0.7

7

1.5

15

Total

100.0

956

100.0

990

Sources: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

Exhibit 7.3.26 Interviewer Reports of Respondent Difficulties, by Consistency Check Status

 

Consistency Check Present

Consistency Check Absent

Item

%

n

%

n

Respondent's Understanding of Interview

       

      No difficulty

84.4

810

81.4

807

      Just a little difficulty

11.7

112

12.9

128

      A fair amount of difficulty

3.1

30

4.3

42

      A lot of difficulty

0.8

8

1.4

14

Total

100.0

960

100.0

991

How Cooperative Was Respondent?

       

      Very cooperative

92.4

888

92.1

913

      Fairly cooperative

6.7

64

7.2

71

      Not very cooperative

0.8

8

0.4

4

      Openly hostile

0.1

1

0.3

3

Total

100.0

961

100.0

991

Respondent's Interest in ACASI

       

      Very interested

62.7

602

59.9

592

      Somewhat interested

32.0

307

34.2

338

      Not very interested

5.3

51

5.9

58

Total

100.0

960

100.0

988

How Necessary Was Tutorial?

       

      Necessary

23.0

221

22.4

221

      Useful but not necessary

50.0

479

50.5

499

      Unnecessary

27.0

260

27.1

268

Total

100.0

960

100.0

988

How Necessary Was Audio?

       

      Necessary

17.4

167

17.9

177

      Useful but not necessary

48.1

461

45.3

448

      Unnecessary

34.5

331

36.8

363

Total

100.0

959

100.0

988

How Often Did Respondent Let Answers Be Known?

       

      None of the time

82.9

796

81.0

800

      A little of the time

12.6

121

13.5

133

      Some of the time

2.8

27

3.5

35

      A lot of the time

1.3

12

1.5

15

      All of the time

0.4

4

0.5

5

Total

100.0

960

100.0

988

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

7.4 Effect of ACASI Experimental Factors: Modeling Procedures and Effects on Prevalence

In this section, we summarize the statistical methods used to assess ACASI experimental factors on the prevalence of drug use, the time to complete different parts of the interview, and the breakoff rates. Logistic regression and Cox proportional hazards models were used to evaluate the various ACASI experimental factors and to compare ACASI versus PAPI on binary and time-to-event responses. Due to the complex sample design, we used the SUrvey DAta ANalysis (SUDAAN) software package Release 7.5 (Shah, Barnwell, & Bieler, 1998) to account for stratification, clustering, and unequal weighting, where appropriate. SUDAAN's LOGISTIC and SURVIVAL procedures were used to fit the regression models. In addition, Release 6.12 of SAS software was used to estimate weighted prevalence rates of drug use, and the SAS procedures PHREG and LIFETEST were used to estimate the unweighted median time to complete different parts of the interview.

The ACASI experimental factors evaluated in this report include the contingent questioning structure (single vs. multiple gate questions), the consistency checks (absent vs. present), and the multiple chances to report use (absent vs. present). Statistical models for evaluating the ACASI experimental factors also included the following covariates:

  1. the field interviewer's (FI's) rating of interview privacy (a three-level categorical variable describing how often the respondent let the FI know his or her answers, coded 1=none of the time, 2=some of the time, and 3=all of the time),

  2. the FI's rating of the degree of nonprivacy/distraction during the interview (coded 1-9, with Level 1 being the most private and Level 9 the least),

  3. age in years (12 to 17 vs. 18 or older),

  4. gender (male vs. female),

  5. education level (less than high school, high school, greater than high school), and

  6. race/ethnicity (Hispanic, black, and white).

In addition to evaluating the main effects of the three experimental factors (contingent questioning structures, multiple use questions, and consistency checks) and covariates, we also evaluated all two-way and three-way interactions among the three ACASI experimental factors.

To compare the ACASI experimental factors on prevalence of drug use, breakoff rates, and the time to complete different parts of the interview, a model containing all the main effects, covariates, and interactions was fit first:

Model 1: Main Effects + Covariates + Interactions

  1. ACASI Main Effects (3 degrees of freedom): (a) contingent questioning, (b) multiple use, and (c) consistency checks.

  2. Covariates (9 degrees of freedom): (a) gender, (b) age group, (c) race/ethnicity, (d) education, (e) letting FI know answers, and (f) degree of distraction/nonprivacy.

  3. Interactions (4 degrees of freedom): (a) contingent questioning * multiple use, (b) contingent questioning * consistency checks, (c) multiple use * consistency checks, and (d) contingent questioning * multiple use * consistency checks.

Wald chi-square tests were used to evaluate the main effects, covariates, and interactions of interest. This interaction model was used to determine if the global 4 degrees-of-freedom interaction effect (containing all two-way and three-way interactions among the ACASI factors) was statistically significant. If the global interaction effect was not significant (p>0.10), all two-way and three-way interactions were removed, and a new main effects model (Model 2 below) was fit containing only ACASI main effects and covariates.

Model 2: Main Effects + Covariates

  1. ACASI Main Effects (3 degrees of freedom): (a) contingent questioning, (b) multiple use, and (c) consistency checks.

  2. Covariates (9 degrees of freedom): (a) gender, (b) age group, (c) race/ethnicity, (d) education, (e) letting FI know answers, and (f) degree of distraction/nonprivacy.

The ACASI experimental factors were then evaluated in the reduced main effects model. In the reduced model, each main effect was automatically adjusted for all other main effects and covariates present in the model.

However, if a significant global interaction effect (4 degrees of freedom) was detected (p<0.10) in Model 1, further modeling was done to evaluate specifically which two-way and possibly three-way interaction effect(s) were statistically significant. When we determined that a particular ACASI experimental factor, X, significantly interacted with another ACASI factor, Y, then factor X was evaluated separately within each level of factor Y (these effects are sometimes called "simple effects" or "effect slices").

The Cox proportional hazards model was used to detect overall heterogeneity in time-to-completion distributions among the ACASI experimental factors. Median event times can be computed from the model. The Cox proportional hazards model is stated as follows:

where t represents the time to event, is the linear combination of covariate effects, and is the relative risk (or hazard ratio) for the event at time t for respondents in different ACASI treatment groups.

Using this model, we were able to quantify the relative effect of treatment combinations on the event times. The model requires the user to supply each respondent's event time, an indicator for censoring ("yes" vs. "no"), and a set of covariate values. All event times, censored and complete, were used in the analysis. A Wald chi-square test was used to evaluate the effect of treatment on event time. The logistic regression model was used to examine the results for prevalence of drug use.

Exhibit 7.4.1 summarizes the statistically significant ACASI treatment effects found. During the analyses, we looked at both unweighted and weighted data for cigarettes, alcohol, marijuana, and cocaine. Exhibit 7.4.1 contains the outcomes of interest, the model effects, the p value(s) and odds ratio(s) corresponding to the effects, and the adjusted prevalence rate. Prevalence rates and model effects were adjusted for all other variables in the model. Odds ratios greater than 1.0 indicate increased prevalence in a particular treatment group versus the reference cell, while odds ratios less than 1.0 indicate reduced prevalence in a particular treatment group.

In the discussion, statistical significance refers to p<0.05 for main effects and p<0.10 for interactions, unless otherwise specified. Marginal significance refers to 0.05< p<0.10. The following summarizes the significant results, both unweighted and weighted:

Cigarettes

  1. The presence of multiple chances to report use significantly reduced the reported prevalence of lifetime use from 59.1% to 53.7% (unweighted only).

  2. The reported prevalence of past month use (weighted only) was marginally increased (0.05< p< 0.10) when respondents had multiple chances to report use (19.9% vs. 29.4% for absent vs. present) and when consistency checks were present (20.4% vs. 28.8% for absent vs. present).

Alcohol

  1. The presence of consistency checks marginally increased (0.05< p<0.10) the reported prevalence of past year use (weighted only) from 67.2% to 74.6%.

  2. The presence of multiple chances to report use significantly reduced the reported prevalence of past month use (unweighted only) from 29.7% to 25.2%.

Marijuana

  1. The multiple gate questions significantly reduced the reported prevalence of past year use (weighted only) from 10.8% to 6.2%.

  2. The presence of consistency checks significantly increased the reported prevalence of past month use (unweighted only) from 4.7% to 8.1% but only for the multiple gate version (this was reflected in a significant interaction effect between the consistency checks and the contingent questioning structure).

Cocaine

  1. Lifetime use was significantly increased in the presence of multiple chances to report use (unweighted only) from 2.9% to 5.5% but only for the multiple gate questions (there was significant interaction between the multiple chances to report use and the type of contingent questioning used).

  2. Lifetime use was significantly reduced when multiple gate questions were used (weighted only, 14.6% vs. 7.4% for single vs. multiple gate).

  3. Past year use was significantly increased in the presence of multiple chances to report use (unweighted and weighted) but only for the multiple gate questions (there was significant interaction between the multiple chances to report use and the contingent questioning structure).

  4. Past year use was significantly reduced in the presence of consistency checks (unweighted and weighted) but only in the presence of multiple chances to report use (there was significant interaction between the consistency checks and the multiple use treatment).

  5. Past month use was significantly increased in the presence of consistency checks (unweighted and weighted) but only for the multiple gate questions (there was significant interaction between the consistency checks and the contingent questioning structure).

  6. Past month use was marginally reduced (0.05<p<0.10, unweighted only) in the presence of consistency checks butonly when respondents had multiple chances to report use (there was significant interaction between the consistency checks and the multiple chances).

Any Illicit Drug Use

  1. Lifetime use was marginally reduced (0.05< p<0.10) in the presence of multiple chances to report use, from 43.1% absent to 38.5% present (unweighted only).

Exhibit 7.4.1 Summary of Statistically Significant Modeling Results: Prevalence of Drug Use Among ACASI Treatment Groups

Outcome

Unweighted or Weighted

Effect

p Value

Odds Ratio

Adjusted Prevalence Rate

Cigarettes

Lifetime

Unweighted

Multiple Use:

Present vs. Absent

0.0144

0.80

59.1% Absent

53.7% Present

Past Month

Weighted

Multiple Use:

Present vs. Absent

0.0780

1.67

19.9% Absent

29.4% Present

   

Consistency Checks:

Present vs. Absent

0.0675

1.58

20.4% Absent

28.8% Present

Alcohol

Past Year

Weighted

Consistency Checks:

Present vs. Absent

0.0817

1.44

67.2% Absent

74.6% Present

Past Month

Unweighted

Multiple Use:

Present vs. Absent

0.0245

0.80

29.7% Absent

25.2% Present

Marijuana

Past Year

Weighted

Multiple vs. Single Gate

0.0179

0.54

10.8% Single

6.2% Multiple

Past Month

Unweighted

Consistency Checks:

Present vs. Absent

(Routing=Multiple Gate)

0.0237

1.93

4.7% Absent

8.1% Present

Cocaine

Lifetime

Unweighted

Multiple Use:

Present vs. Absent

(Routing=Multiple Gate)

0.0165

2.45

2.9% Absent

5.5% Present

Lifetime

Weighted

Multiple vs. Single Gate

0.0280

0.47

14.6% Single

7.4% Multiple

Past Year

Unweighted

Multiple Use:

Present vs. Absent

(Routing=Multiple Gate)

0.0124

--

1.2% Absent

2.5% Present

   

Consistency Check:

Present vs. Absent

(Multiple Use=Present)

0.0162

--

3.3% Absent

1.2% Present

Past Year

Weighted

Multiple Use:

Present vs. Absent

(Routing=Multiple Gate)

0.0079

--

0.4% Absent

1.5% Present

   

Consistency Check:

Present vs. Absent

(Multiple Use=Present)

0.0079

--

2.3% Absent

0.6% Present

Past Month

Unweighted

Consistency Check:

Present vs. Absent

(Routing=Multiple Gate)

0.0397

--

0.24% Absent

0.61% Present

   

Consistency Check:

Present vs. Absent

(Multiple Use=Present)

0.0690

--

0.88% Absent

0.26% Present

Past Month

Weighted

Consistency Check:

Present vs. Absent

(Routing=Multiple Gate)

0.0032

11.03

0.07% Absent

0.44% Present

Any Illicit Drug Use

Lifetime

Unweighted

Multiple Use:

Present vs. Absent

0.0633

0.88

43.1% Absent

38.5% Present

1 Any illicit drug includes marijuana, cocaine, crack, heroin, inhalants, hallucinogens, and nonmedical use of analgesics, sedatives, stimulants, and tranquilizers.

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures: 1997 Field Experiment.

7.5 Effect of ACASI Experimental Factors on the Time to Complete Different Parts of the Interview

We calculated the unweighted median time to complete different parts of the interview for each of the eight ACASI treatment combinations. Cox Proportional Hazards Regression Modeling was used to evaluate the effects of ACASI experimental factors on the completion times for the following three outcomes of interest:

  1. the total core time (all CAI sections through the sedatives section),

  2. the core experimental time (tobacco through inhalants sections), and

  3. the remaining ACASI time (from inhalants to the end).

For each time variable, respondents who were not at risk at the start of the reference period had a missing value for that time variable and were therefore not included in the analysis. Respondents who broke off during the reference period were censored during that time and had a censoring indicator value corresponding to "yes." Their time value contains partial information that was used in this analysis.

The following information summarizes the significant results for each variable. We fit models using both weighted and unweighted data; however, only the unweighted results are presented because they apply to the actual sample. This is most appropriate for an operational measure.

7.5.1 Total Core Time, Unweighted

  1. Multiple gate versions significantly delayed the time to completion compared to the single gate version (18.65 vs. 17.58 minutes with an estimated hazard ratio of 0.84, p<0.01).

  2. Multiple chances to report use significantly delayed the time to completion (the median time to complete was 18.42 vs. 17.77 minutes with an estimated hazard ratio of 0.90, p<0.01).

  3. There was no significant effect on time to complete based on whether consistency checks were present or absent.

  4. Among the covariates, age, education, race/ethnicity, and the degree of non-privacy/distraction had significant effects on the time to complete, with significantly shortened times for those aged 12 to 17 years compared to those aged 18 or older but significantly delayed times for those with less thana high school education and high school graduates compared to those with more than a high school education, for Hispanics and blacks compared to whites, and for every unit increase in distraction.

7.5.2 Core Treatment Time (Tobacco Through Inhalants), Unweighted

  1. Multiple gate versions significantly delayed the time to completion compared to the single gate version (the median time to complete was 10.6 vs. 9.77 minutes for multiple vs. single gate, respectively, with the estimated hazard ratio at 0.80, p<0.01).

  2. Multiple chances to report use significantly delayed the time to completion (the median time to complete was 10.3 vs. 9.95 minutes for presence vs. absence, respectively, with the hazard ratio at 0.89, p=0.014).

  3. The presence of consistency checks also significantly delayed the time to completion (the median time to complete was 10.27 vs. 9.97 minutes for the presence vs. absence of consistency checks, with an estimated hazard ratio of 0.91, p=0.028).

  4. Among the covariates, age group, education, race/ethnicity, letting the FI know the answers, and the degree of nonprivacy/distraction had significant effects on time to complete, with significantly shortened times for those aged 12 to 17 years compared to those aged 18 years or older, but with significantly delayed times for those with less than high school education and high school graduates compared to those with more than a high school education, Hispanics compared to whites, letting the FI know the answers some of the time compared to all of the time, and for every unit increase in distraction. Hazard ratios for shortened times were greater than 1.0, while hazard ratios for delayed times were less than 1.0.

  5. We examined the impact of the time required to complete the core on subsequent breakoffs. The analysis was based on only those respondents who were not censored before or during the core treatment sections (n=1,968) or, in other words, at risk for subsequent breakoff. No other covariates or treatment factors were included in the model. Results indicate that subsequent breakoff after core treatment was significantly associated with a delay in the median time to complete the core treatment. The median times were 10.7 versus 10.05 minutes for the presence versus absence of subsequent breakoff, with an estimated hazard ratio of 0.84, p=0.033.

7.5.3 Remaining ACASI Time After Inhalants, Unweighted

Although ACASI treatments did not vary in this section, we examined these times to determine if the treatment assigned to a respondent in the tobacco through inhalants sections had a carryover effect.

  1. None of the previously assigned ACASI experimental factors had a significant effect on the time to complete the remaining ACASI after the inhalants section.

  2. Among the covariates, education, race/ethnicity, and the degree of non-privacy/distraction had significant effects on the time to complete, with significantly delayed times for those with less than a high school education and high school graduates compared to those with a high school education, Hispanics and blacks compared to whites, and for every unit increase in distraction. Hazard ratios for delayed times were less than 1.0.

Although there were multiple results that were significantly different, none of the time differences was large enough to point toward choosing one method over another.

7.6 Effect of ACASI Experimental Factors on Breakoff Rates

In this section, we describe the results of logistic regression modeling to evaluate the effects of ACASI experimental factors on the incidence of breakoffs anywhere in the interview.

Some additional information corresponding to these analyses and results follows. We present only unweighted modeling results. A table of results (Exhibit 7.6.1) contains the model effects and their corresponding p value(s) and odds ratio(s). Odds ratios greater than 1.0 indicate an increase in the probability of a breakoff for a particular group compared to the reference group, and an odds ratio less than 1.0 indicates a reduction in the probability of a breakoff. Effects are adjusted for all other variables in the model, unless otherwise indicated. Statistical significance refers to p<0.05, unless otherwise specified. The 12 to 17 year olds were classified as less than high school graduates to include all respondents in one analysis. Privacy covariates were not included in this model because their missing values would have removed all but four breakoffs from the analysis. A total of 32 breakoff cases out of 1,982 respondents were used in this analysis.

The following information summarizes the results from this analysis. None of the ACASI experimental factors significantly affected the incidence of breakoffs. None of the covariates significantly affected the incidence of breakoffs.

Exhibit 7.6.1 Logistic Regression Modeling Results: Breakoff Anywhere in the Interview (Unweighted Results)

Outcome

Effect

Contrast

p Value

Odds Ratio

Intstat:

Breakoff indicator

(1=yes; 0=no)

Interactions

Involving Main Effects (4 df):

-

0.1372

--

 

Contingent Questioning Structure

Multiple Gate vs.

Single Gate

0.6170

1.20

 

Multiple Chance

Present vs. Absent

0.8004

1.10

 

Consistency Checks

Present vs. Absent

0.8636

1.05

 

Gender

Male vs. Female

0.3224

1.49

 

Age Group

12-17 vs. 18+

0.9633

1.03

 

Education

Overall (2 df)

0.7550

 
   

< High School vs.

> High School

0.7139

0.76

   

High School vs.

> High School

0.4573

0.61

 

Race

Overall (2 df)

0.9692

 
   

Hispanic vs. White

0.8876

0.92

   

Black vs. White

0.8653

1.07

Note: There were 32 break off cases out of 1,982 respondents. Privacy covariates are not included in this model because their missing values would remove all but four break off from the analysis.

Source: National Household Survey on Drug Abuse: Development of Computer-Assisted Interviewing Procedures; 1997 Field Experiment.

16 Only possible for respondents assigned to the multiple use treatment.

17 Patterns of inconsistent reporting are discussed more fully in Sections 7.1.2, 7.2.2, and 7.3.2.

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This page was last updated on June 16, 2008.