Retention & Reasons for Noninterview

Retention vs. response rate

Retention rates for NLSY79 respondents from 1979 to 1993 exceeded 90 percent. Rates from 1994 until 2000 exceeded 80 percent. Rates from 2002 until 2014 were in the 70s. Retention rate is calculated by dividing the number of respondents interviewed by the number of respondents remaining eligible for interview. All 1979 (round 1) respondents including those reported as deceased are eligible for interviews, with the exception of those who have been permanently dropped from the sample. In the round 29 (2020) survey, 6,535 civilian and military respondents out of the 9,964 eligible were interviewed, for an overall retention rate of 65.6 percent. Retention rates for each survey are shown in Table 1. This table also shows which interviews were conducted with paper-and-pencil interviewing (PAPI) and which were executed with computer-assisted personal interviewing (CAPI).

The number of respondents can also be expressed as a percentage of the number of base year respondents not known to be deceased. This is referred to as the response rate and is reported in Table 2 for each survey round. As of 2020, 1,185 main respondents had been reported as deceased. The response rate for those believed to be alive is 74.4 percent.

Reasons for noninterview

A 'Reason for Noninterview' variable is constructed for each survey year (excluding 1979) in the NLSY79 and provides an explanation of why an interview could not be conducted or completed with a respondent. The cause of noninterview is assigned by the NORC interviewer to each respondent designated as a member of the eligible sample for a given survey year. Typical coding categories have included reasons such as an interview being refused by the respondent or by the respondent's parent, the respondent or family unit not being located, or the respondent being reported as deceased.

Beginning in the 1980s, two administrative categories were added. One reflected a decision by NORC not to attempt to interview certain sample members who were determined to be extremely difficult to interview. The second category indicates that, due to funding cutbacks, interviews would not be attempted with certain members of one or more of the NLSY79 subsamples. Thus, beginning in 1985, interviews ceased for 1,079 respondent members of the military subsample; each was permanently assigned a reason for noninterview of "military sample dropped." A second group of respondents, those belonging to the supplemental economically disadvantaged, nonblack/non-Hispanic sample, was similarly dropped from interviewing beginning with the 1991 survey. The target universe for each survey year--that is, the respondents whom NORC attempts to interview--thus includes all respondents interviewed in the initial survey year exclusive of those who were:

1. reported deceased at an earlier interview
2. dropped from the sample
3. judged to be extremely difficult to interview

Table 3 presents the number of respondents not interviewed across survey years by sample type.

Sample representativeness and 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 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.