NATIONAL HOUSEHOLD SURVEY ON DRUG ABUSE: evaluation

1997 National Household Survey on Drug Abuse

Evaluation of the 1997 NHSDA

In the tables and discussion that follow, an assessment of the 1997 NHSDA is presented in terms of screening and interviewing response rates (including numbers of interviews targeted and achieved), interviewers' perceptions of respondents' cooperation and comprehension, and number of visits necessary to achieve the interviews.

Screening and interviewing response rates. Table B.1 presents the screening response results for the total United States, the Arizona/California supplemental strata, and the total United States, excluding the Arizona/California supplemental strata. The overall screening response rate for eligible cases was 92.7%. Screenings not completed are identified by reason. Refusals (3%) and inability to contact a potential respondent (2%) resulted in the highest proportions of incomplete screenings.

Interview response rates are presented in Table B.2 by age group and race/ethnicity. The interview response rate was 78.3% across the sample of 31,290 eligible housing unit members. Response rates tended to be inversely related to age, with the highest response rate (82.8%) among 12- to 17-year-old sample members. Conversely, refusal rates rose slightly with age. Hispanics had higher response rates than did non-Hispanic sample members. The inability to find the selected person at home was lowest among Hispanics. Response rates by race/ethnicity ranged from 75.5% for whites to 82.5% for Hispanics.

Table B.3 presents interview response rates by age group and region, Table B.4 by race/ethnicity and region, and Table B.5 by race/ethnicity and population density. Response rates varied by region and were generally higher in the South and Northeast, and lower in the North Central and West. Overall, the lowest response rates were found among non-Hispanic whites living in the West and among those aged 35 or older living in the West (69% to 66%). The highest response rates were found among blacks not living in metropolitan statistical areas (i.e., non-MSAs) (93%) and Hispanics living in the Northeast (90%).

Number of visits and response rates. Table B.6 shows the results of initial and repeated visits to SDUs to complete a household screening and to obtain an interview. Nearly half (49.7%) of all interviews were completed on the initial visit, and more than 80% of all interviews had been completed after three visits. Up to 9 callbacks yielded still substantial increases in the number of interviews completed (95.5%), but 10 or more callbacks resulted in only slight improvements in the overall response rate.

Privacy and respondent cooperation and comprehension. Based on interviewers' assessments, most of the interviews were conducted in complete privacy, as shown in Table B.7. Nearly 80% of the interviews, in each racial/ethnic group, were virtually undisturbed, with only minor distractions occurring. Interviews with whites were more likely to be completely private than those with Hispanics or blacks. Among blacks, 10% of the interviews were completed with another person constantly present. The youngest age group, 12 to 17 year olds, was the most likely to have another person constantly present during an interview (9.5% to 14.3%).

The vast majority of the respondents were rated as very cooperative by interviewers, as shown in Table B.8. At least 98% of respondents in each racial/ethnic category were reported as being very or fairly cooperative. Most respondents-more than 89% of each racial/ethnic group-were perceived as experiencing only a little or no difficulty in level of understanding during the interview.


Table B.1 Number and Percentage of Sampled Housing Units Screened, 1997
	U.S. Excluding AZ/CA		AZ/CA		Total U.S.
Screening Results	n	Percent-age	n	Percent-age	n	Percent-age
Total Sample Ineligible cases Eligible cases	53,890 8,603 45,287	100.0 16.0 84.0	41,442 5,661 35,781	100.0 13.7 86.3	95,332 14,264 81,068	100.0 15.0 85.0
Ineligible Cases Vacant Not primary residence Not a dwelling unit Other ineligible	8,603 6,379 1,103 1,058 63	100.0 74.1 12.8 12.3 0.8	5,661 4,144 709 701 107	100.0 73.2 12.5 12.4 1.9	14,264 10,523 1,812 1,759 170	100.0 73.8 12.7 12.3 1.2
Eligible Cases Screening completed Selected for interview Not selected for interview	45,287 42,705 14,262 28,443	100.0 94.3 31.5 62.8	35,781 32,431 10,555 21,876	100.0 90.6 29.5 61.1	81,068 75,136 24,817 50,319	100.0 92.7 30.6 62.1
Screening not completed No one at home Respondent unavailable Physical/mental incompetent Language barrier-Hispanic Language barrier-other Refusal Other, eligible Other, access denied Segment not accessible Screener not returned Fraudulent case	2,582 937 79 27 39 71 1,055 9 208 0 154 3	5.7 2.1 0.2 0.1 0.1 0.2 2.3 0.0 0.5 0.0 0.3 0.0	3,350 822 58 24 9 117 1,324 1 381 150 394 70	9.4 2.3 0.2 0.1 0.0 0.3 3.7 0.0 1.1 0.4 1.1 0.2	5,932 1,759 137 51 48 188 2,379 10 589 150 548 73	7.3 2.2 0.2 0.1 0.1 0.2 2.9 0.0 0.7 0.2 0.7 0.1

AZ = Arizona; CA = California.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997.


Table B.2 Interview Results, by Age Group and Race/Ethnicity, 1997
	Age Group in Years
	12-17		18-25		26-34		$35		Total
Race/Ethnicity	n	Percent-age	n	Percent-age	n	Percent-age	n	Percent-age	n	Percent-age
Hispanic Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	2,398 2,086 26 51 100 135	100.0 87.0 1.1 2.1 4.2 5.6	2,319 1,863 50 139 6 261	100.0 80.3 2.2 6.0 0.3 11.3	1,381 1,134 30 104 0 113	100.0 82.1 2. 2 7.5 0.0 8.2	1,489 1,176 22 138 1 152	100.0 79.0 1.5 9.3 0.1 10.2	7.587 6.259 128 432 107 661	100.0 82.5 1.7 5.7 1.4 8.7
Black, Non-Hispanic Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	1,591 1,346 37 33 71 104	100.0 84.6 2.3 2.1 4.5 6.5	1,296 1,062 42 77 2 113	100.0 81.9 3.2 5.9 0.2 8.7	1,453 1,184 52 111 3 103	100.0 81.5 3.6 7.6 0.2 7.1	1,331 1,047 42 120 1 121	100.0 78.7 3.2 9.0 0.1 9.1	5,671 4,639 173 341 77 441	100.0 81.8 3.1 6.0 1.4 7.8
White, Non-Hispanic Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	5,481 4,412 48 215 500 306	100.0 80.5 0.9 3.9 9.1 5.6	4,537 3,314 136 513 23 551	100.0 73.0 3.0 11.3 0.5 12.1	2,638 2,069 76 293 2 198	100.0 78.4 2.9 11.1 0.1 7.5	5,376 3,812 117 858 3 586	100.0 70.9 2.2 16.0 0.0 10.9	18,032 13,607 377 1,879 528 1,641	100.0 75.5 2.1 10.4 2.9 9.1
Total Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	9,470 7,844 111 299 671 545	100.0 82.8 1.2 3.2 7.1 5.8	8,152 6,239 228 729 31 925	100.0 76.5 2.8 8.9 0.4 11.3	5,472 4,387 158 508 5 414	100.0 80.2 2.9 9.3 0.1 7.6	8,196 6,035 181 1,116 5 859	100.0 73.6 2.2 13.6 0.1 10.5	31,290 24,505 678 2,652 712 2,743	100.0 78.3 2.2 8.5 2.3 8.8

HU = housing unit.

¹Parental refusals for persons aged 26 or older were considered unlikely and may have been incorrectly coded by interviewers.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997.


Table B.3 Interview Results, by Age Group and Region, 1997
	Age Group in Years
	12-17		18-25		26-34		$35		Total
Region	n	Percent-age	n	Percent-age	n	Percent-age	n	Percent-age	n	Percent-age
Northeast Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	956 843 14 9 32 58	100.0 88.2 1.5 0.9 3.3 6.1	743 618 20 30 1 74	100.0 83.2 2.7 4.0 0.1 10.0	798 684 17 35 0 62	100.0 85.7 2.1 4.4 0.0 7.8	886 760 21 40 0 65	100.0 85.8 2.4 4.5 0.0 7.3	3,383 2,905 72 114 33 259	100.0 85.9 2.1 3.4 1.0 7.7
North Central Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	1,208 992 19 40 97 60	100.0 82.1 1.6 3.3 8.0 5.0	954 731 32 98 2 91	100.0 76.6 3.4 10.3 0.2 9.5	982 2 30 109 3 78	100.0 77.6 3.1 11.1 0.3 7.9	1,031 770 35 131 0 95	100.0 74.7 3.4 12.7 0 9.2	4,175 3,255 116 378 102 324	100.0 78.0 2.8 9.1 2.4 7.8
South Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	2,499 2,226 33 47 98 95	100.0 89.1 1.3 1.9 3.9 3.8	2,027 1,733 64 105 1 124	100.0 85.5 3.2 5.2 0.0 6.1	2,075 1,765 61 141 1 107	100.0 85.1 2.9 6.8 0.0 5.2	2,240 1,830 48 195 0 167	100.0 81.7 2.1 8.7 0.0 7.5	8,841 7,554 206 488 100 493	100.0 85.4 2.3 5.5 1.1 5.6
West Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	4,807 3,783 45 203 444 332	100.0 78.7 0.9 4.2 9.2 6.9	4,428 3,157 112 496 27 636	100.0 71.3 2.5 11.2 0.6 14.4	1,617 1,176 50 223 1 167	100.0 72.7 3.1 13.8 0.1 10.3	4,039 2,675 77 750 5 532	100.0 66.2 1.9 18.6 0.1 13.2	14,891 10,791 284 1,672 477 1,667	100.0 72.5 1.9 11.2 3.2 11.2

Total
Eligible HU members
Interview completed
No respondent home
Refusal
Parental refusal¹
Other

9,470
7,844
111
299
671
545

100.0
82.8
1.2
3.2
7.1
6.9

8,152
6,239
228
729
31
925

100.0
76.5
2.8
8.9
0.4
11.3

5,472
4,387
158
508
5
414

100.0
80.2
2.9
9.3
0.1
7.6

8,196
6,035
181
1,116
5
859

100.0
73.6
2.2
13.6
0.1
10.5

31,290
24,505
678
2,652
712
2,743

100.0
78.3
2.2
8.5
2.3
8.8

HU = housing unit.

¹Parental refusals for persons aged 26 or older are considered unlikely and may have been incorrectly coded by interviewers.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997.


Table B.4 Interview Results, by Race/Ethnicity and Region, 1997
	Hispanic		Black, Non-Hispanic		White, Non-Hispanic		Total
Region	n	Percent-age	n	Percent-age	n	Percent-age	n	Percent-age
Northeast Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	745 668 8 9 5 55	100.0 89.7 1.1 1.2 0.7 7.4	808 661 25 32 7 83	100.0 81.8 3.1 4.0 0.9 10.3	1,830 1,576 39 73 21 121	100.0 86.1 2.1 4.0 1.1 6.6	3,383 2,905 72 114 33 259	100.0 85.9 2.1 3.4 1.0 7.7
North Central Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	355 302 3 12 1 37	100.0 85.1 0.8 3.4 0.3 10.4	935 695 46 81 20 93	100.0 74.3 4.9 8.7 2.1 9.9	2,885 2,258 67 285 81 194	100.0 78.3 2.3 9.9 2.8 6.7	4,175 3,255 116 378 102 324	100.0 78.0 2.8 9.1 2.4 7.8
South Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	2,063 1,784 52 74 13 140	100.0 86.5 2.5 3.6 0.6 6.8	3,158 2,736 82 144 27 169	100.0 86.6 2.6 4.6 0.9 5.4	3,620 3,034 72 270 60 184	100.0 83.8 2.0 7.5 1.7 5.1	8,841 7,554 206 488 100 493	100.0 85.4 2.3 5.5 1.1 5.6
West Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	4,424 3,505 65 337 88 429	100.0 79.2 1.5 7.6 2.0 9.7	770 547 20 84 23 96	100.0 71.0 2.6 10.9 3.0 12.5	9,697 6,739 199 1,251 366 1,142	100.0 69.5 2.1 12.9 3.8 11.8	14,891 10,791 284 1,672 477 1,667	100.0 72.5 1.9 11.2 3.2 11.2

Total
Eligible HU members
Interview completed
No respondent home
Refusal
Parental refusal¹
Other

7,587
6,259
128
432
107
661

100.0
82.5
1.7
5.7
1.4
8.7

5,671
4,639
173
341
77
441

100.0
81.8
3.1
6.0
1.4
7.8

18,032
13,607
377
1,879
528
1,641

100.0
75.5
2.1
10.4
2.9
9.1

31,290
24,505
678
2,652
712
2,743

100.0
78.3
2.2
8.5
2.3
8.8

HU = housing unit.

¹Parental refusals for persons aged 26 or older are considered unlikely and may have been incorrectly coded by interviewers.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997.


Table B.5 Interview Results, by Race/Ethnicity and Population Density, 1997
	Hispanic		Black, Non-Hispanic		White, Non-Hispanic		Total
Population Density	n	Percent-age	n	Percent-age	n	Percent-age	n	Percent-age
1,000,000+ Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	4,983 4,109 82 285 65 442	100.0 82.5 1.6 5.7 1.3 8.9	3,166 2,447 117 246 53 303	100.0 77.3 3.7 7.8 1.7 9.6	8,860 6,408 224 971 306 951	100.0 72.3 2.5 11.0 3.5 10.7	17,009 12,964 423 1,502 424 1,696	100.0 76.2 2.5 8.8 2.5 10.0
50,000 to 999,999 Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	1,988 1,657 35 110 30 156	100.0 83.4 1.8 5.5 1.5 7.8	1,629 1,380 47 77 21 104	100.0 84.7 2.9 4.7 1.3 6.4	5,320 4,100 90 563 143 424	100.0 77.1 1.7 10.6 2.7 8.0	8,937 7,137 172 750 194 684	100.0 79.9 1.9 8.4 2.2 7.7
Non-MSA Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	616 493 11 37 12 63	100.0 80.0 1.8 6.0 1.9 10.2	876 812 9 18 3 34	100.0 92.7 1.0 2.1 0.3 3.9	3,852 3,099 63 345 79 266	100.0 80.5 1.6 9.0 2.1 6.9	5,344 4,404 83 400 94 363	100.0 82.4 1.6 7.5 1.8 6.8
Total Eligible HU members Interview completed No respondent home Refusal Parental refusal¹ Other	7,587 6,259 128 432 107 661	100.0 82.5 1.7 5.7 1.4 8.7	5,671 4,639 173 341 73 445	100.0 81.8 3.1 6.0 1.3 7.8	18,032 13,607 377 1,879 523 1,646	100.0 75.5 2.1 10.4 2.9 9.1	31,290 24,505 678 2,652 712 2,743	100.0 78.3 2.2 8.5 2.3 8.8

HU = housing unit; MSA = metropolitan statistical area.

¹Parental refusals for persons aged 26 or older are considered unlikely and may have been incorrectly coded by interviewers.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997.

Table B.6 Number of Visits Required to Complete Interviews, 1997

Visits	Interviews	Percentage	Cumulative Percentage
1 2 3 4 5-9 10+ Missing	12,187 5,508 2,020 1,186 2,502 254 844	49.7 22.5 8.2 4.8 10.2 1.0 3.4	49.7 72.2 80.5 85.3 95.5 96.5 100.0
Total	24,505	--	--

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997


Table B.7 Interviewer's Assessment of Respondent's Level of Privacy During Interview, by Age and Ethnicity of Respondent, 1997
Race/Ethnicity and Interviewer Assessment	Age Group in Years
Race/Ethnicity and Interviewer Assessment	12-17	18-25	26-34	$35	Total
Hispanic
Total number Level of privacy (percentage of total) 01 - Completely private 02 - 03 - Minor distractions 04 - 05 - Person(s) in room 1/3 of time 06 - 07 - Serious interruptions > � time 08 - 09 - Constant presence of other people 10 - Not sure	2,086 53.4 4.3 20.8 1.3 7.8 0.3 1.2 0.3 9.5 1.2	1,863 60.2 3.5 21.1 1.5 4.5 0.3 1.2 0.0 6.6 1.1	1,134 61.6 2.8 19.2 1.2 5.8 0.0 1.7 0.2 6.1 1.4	1,176 64.6 2.8 16.5 0.8 5.5 0.0 1.3 0.1 6.9 1.5	6,259 59.0 3.5 19.8 1.3 6.0 0.2 1.3 0.2 7.5 1.2
Black, Non-Hispanic
Total number Level of privacy (percentage of total) 01 - Completely private 02 - 03 - Minor distractions 04 - 05 - Person(s) in room 1/3 of time 06 - 07 - Serious interruptions > � time 08 - 09 - Constant presence of other people 10 - Not sure	1,346 49.5 2.8 15.6 0.5 12.8 1.2 1.7 0.2 14.3 1.3	1,062 64.0 2.7 16.0 0.7 4.9 0.1 1.8 0.1 8.8 0.9	1,184 67.3 2.4 13.8 0.6 4.5 0.3 1.9 0.2 7.7 1.4	1,047 69.4 2.9 11.2 0.2 4.9 0.5 1.4 0.1 8.5 1.0	4,639 61.9 2.7 14.2 0.5 7.1 0.6 1.7 0.2 10.0 1.2
White, Non-Hispanic
Total number Level of privacy (percentage of total) 01 - Completely private 02 - 03 - Minor distractions 04 - 05 - Person(s) in room 1/3 of time 06 - 07 - Serious interruptions > � time 08 - 09 - Constant presence of other people 10 - Not sure	4,412 55.4 3.6 17.7 0.7 9.4 0.3 1.1 0.1 10.0 1.7	3,314 68.8 1.8 13.7 0.8 5.3 0.3 1.3 0.2 6.6 1.2	2,069 64.2 2.8 16.9 1.1 5.3 0.1 1.0 0.0 7.7 0.9	3,812 74.5 1.8 10.5 0.6 4.6 0.1 1.0 0.1 5.6 1.1	13,607 65.4 2.5 14.6 0.7 6.4 0.2 1.1 0.1 7.6 1.3

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997.


Table B.8 Interviewer's Assessment of Respondent's Level of Cooperation and Understanding, by Age and Ethnicity of Respondent, 1997
Race/Ethnicity and Interviewer Assessment	Age Group in Years
Race/Ethnicity and Interviewer Assessment	12-17	18-25	26-34	$35	Total
Hispanic
Total number Level of cooperation (percentage of total) Very cooperative Fairly cooperative Not very cooperative Openly hostile No response	2,086 90.0 8.5 0.8 0.0 0.7	1,863 86.6 11.6 1.3 0.0 0.4	1,134 88.7 9.5 0.7 0.0 1.1	1,176 85.9 12.0 1.5 0.2 0.4	6,259 88.0 10.3 1.1 0.0 0.6
Level of understanding (percentage of total) No difficulty Just a little difficulty A fair amount of difficulty A lot of difficulty No response	74.2 17.2 5.1 0.8 2.7	75.0 15.1 5.1 1.8 3.0	73.2 14.9 5.6 3.0 3.4	66.3 17.3 9.0 5.6 1.7	72.8 16.2 5.9 2.4 2.7
Black, Non-Hispanic
Total number Level of cooperation (percentage of total) Very cooperative Fairly cooperative Not very cooperative Openly hostile No response	1,346 89.6 8.2 1.0 0.5 0.7	1.062 87.9 10.0 1.5 0.2 0.5	1,184 86.0 10.6 2.0 0.7 0.8	1,047 84.0 12.9 1.9 0.6 0.7	4,639 87.0 10.3 1.6 0.5 0.6
Level of understanding (percentage of total) No difficulty Just a little difficulty A fair amount of difficulty A lot of difficulty No response	73.0 16.9 5.2 1.9 3.0	82.3 10.1 2.9 1.0 3.7	82.2 10.0 2.4 1.0 4.4	71.7 12.7 7.3 4.5 3.8	77.2 12.6 4.4 2.1 3.7
White Non-Hispanic
Total number Level of cooperation (percentage of total) Very cooperative Fairly cooperative Not very cooperative Openly hostile No response	4,412 93.3 5.3 0.5 0.2 0.8	3,314 92.6 6.2 0.5 0.2 0.5	2,069 92.5 6.3 0.7 0.1 0.5	3,812 90.1 8.0 0.9 0.2 0.8	13,607 92.1 6.4 0.6 0.2 0.7
Level of understanding (percentage of total) No difficulty Just a little difficulty A fair amount of difficulty A lot of difficulty No response	83,7 10.2 2.4 0.5 3.1	89.5 5.7 1.4 0.6 2.7	90.4 5.0 1.2 1.0 2.4	83.2 8.4 3.0 1.9 3.5	85.0 7.8 2.1 1.0 3.0

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1997.

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