Retention & Reasons for Noninterview

Sample Representativeness & Attrition

This section reviews the number of respondents by race, sex, and NLSY79 sample type who have continued to be interviewed during all surveys. It also takes a brief look at the racial composition of the cohort at the initial and latest survey points. Table 4 shows the number of respondents, excluding dropped respondents, who were interviewed at all survey points. This table exhibits the high degree of NLSY79 retention. From 1979 to 2020 the survey has been administered 29 times.

Table 4. Percentage of NLSY79 Respondents, Excluding Dropped Respondents, Who Answered Every Survey: 1979-2020

Year	Percent	Number	Year	Percent	Number
1979	100%	9964	1993	73.2%	7291
1980	96.0%	9571	1994	71.8%	7153
1981	94.3%	9395	1996	69.6%	6935
1982	92.7%	9234	1998	69.9%	6664
1983	91.6%	9125	2000	63.3%	6310
1984	89.7%	8942	2002	60.3%	6004
1985	87.5%	8721	2004	57.6%	5736
1986	85.0%	8472	2006	55.6%	5538
1987	82.3%	8203	2008	54.3%	5407
1988	79.9%	7957	2010	52.3%	5208
1989	78.5%	7819	2012	50.3%	5012
1990	76.7%	7642	2014	48.0%	4787
1991	75.5%	7521	2016	46.3%	4613
1992	74.2%	7396	2018	44.7%	4452
			2020	42.5%	4239

Table 5 shows the distribution of the number of interviews completed by respondents, broken down by sample type. The "# who completed" column shows how many respondents completed exactly that number of surveys. These numbers refer to any surveys completed since the NLSY79 began, not necessarily consecutive surveys completed or surveys completed in particular years. The cumulative percent column shows a cumulative total percent of those completing at least a given number of surveys rather than a percentage of those completing an exact number of surveys. Readers should note the attrition suggested in Table 3 greatly overstates the amount of lost information. The NLSY79 asks detailed questions about work history, education, training, marital status, and fertility since the date of the respondent's last interview. These retrospective questions capture information lost due to missed interviews. Hence, a perfect response record is not needed for researchers to understand how the respondent's life changes over time, unless he or she leaves the survey forever.

Table 5. Number of Interviews Respondents Completed out of 29 Surveys by Sample Type: NLSY79 1979-2020

	Total Sample		Cross Sectional Sample		Supplemental Sample		Military Sample
# of Surveys¹	# who Completed	Cumul. Percent	# who Completed	Cumul. Percent	# who Completed	Cumul. Percent	# who Completed	Cumul. Percent
1	39	0.4	25	0.4	14	0.4	0	-
2	38	0.4	22	0.4	15	0.4	1	0. 5
3	29	0.3	19	0.3	10	0.3	0	-
4	38	0.4	17	0.3	19	0.5	2	1.0
5	48	0.5	35	0.6	12	0.3	1	0.5
6	61	0.6	36	0.6	25	0.7	0	-
7	70	0.7	50	0.8	18	0.5	2	1.0
8	65	0.7	42	0.7	22	0.6	1	0.5
9	80	0.8	49	0.8	31	0.8	0	-
10	70	0.7	47	0.8	22	0.6	1	0.5
11	71	0.7	36	0.6	35	1.0	0	-
12	79	0.8	55	0.9	22	0.6	2	1.0
13	96	0.9	62	1.0	34	0.9	0	-
14	105	1.1	69	1.1	35	1.0	1	0.5
15	108	1.1	69	1.1	37	1.0	2	1.0
16	163	1.6	101	1.7	57	1.6	5	2.5
17	161	1.6	116	1.9	42	1.2	3	1.5
18	206	2.1	134	2.2	65	1.8	7	3.5
19	205	2.1	131	2.1	70	1.9	4	2.0
20	235	2.4	147	2.4	82	2.2	6	3.0
21	227	2.3	134	2.2	87	2.4	6	3.0
22	255	2.6	147	2.4	100	2.7	8	4.0
23	310	3.1	177	2.9	122	3.3	11	5.5
24	340	3.4	196	3.2	137	3.8	7	3.5
25	416	4.2	261	4.3	150	4.1	5	2.5
26	498	5.0	267	4.4	213	5.8	18	9.0
27	625	6.3	333	5.4	275	7.5	17	8.5
28	1087	10.9	622	10.2	446	12.2	19	9.5
29	4239	42.5	2712	44.4	1455	40.0	72	35.8
Total	9964	100%	6111	100%	3652	100%	201	100%

Note: Universe excludes the 1,079 members of the military subsample and the 1,643 members of the economically disadvantaged, non-black/non-Hispanic oversample dropped from interviewing; it includes the remaining 9,964 eligible members.
¹Surveys completed in any year, not necessarily consecutive survey years.

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Retention & Reasons for Noninterview