After each round of the NLSY97, validation reinterviews are conducted with randomly selected respondents. Validation data for many of the rounds are available to public users and offer opportunities for studying response variance, item reliability, and other methodological issues.
Approximately 10% of completed interviews are validated every round. The main goals of the reinterview are to assess the quality of the interview data and to make sure the interview was done properly. To confirm that the interview was conducted properly, respondents are asked whether the interview took place, length of the interview, mode of the interview, number of sessions required, and whether the incentive payments were made. To assess data quality, respondents are asked a few questions from the survey. Some of these questions change from year to year. The data are analyzed to compare the responses in the interview and validation reinterview. The selected items are items most respondents will have answered in the main interview and represent a range of expected reliability, including items that are likely to agree between interview and reinterview as well as items that may disagree.
Cases are selected to achieve 10% validation of each interviewer's caseload. The current validation system is designed to select randomly approximately 13% of each interviewer's completed cases for validation. Additional cases are included for validation if there is concern about some aspect of the interview. The majority of validation interviews are completed within three weeks of the main interview date. Occasionally, a small number of reinterviews have been conducted by mail or in person.
The data from validation can be used to study the consistency of responses between the interview and reinterview. Estimates of simple response variances can be calculated from the validation data. For instance, in rounds 2 through 4 it was found that the proportion of cases where the interview and reinterview responses did not match (mismatch rate) was quite low for many factual questions such as the type of housing of the respondent, the highest grade attended, or whether the respondent reported having any income. Some of these differences could be due to differences in question wording or mode and may be affected by the length of the recall period. However, in round 4, the mismatch rate was high for questions about expectations, showing that the respondent's expectations were quite unstable. The validation data can also provide interesting insights about interviewer performance, both positive and negative.
Although reinterviews have been administered each year since round 2, the validation variables for rounds 2, 3, and 11 and up were not released to public users. The public variables, described below, have "VALIDRx" as the beginning of each question name and are found in the main file data set.
Round 4. Between November 2000 and July 2001, 989 respondents completed validation reinterviews for round 4. This produced an overall project validation rate of 11.9 percent of completed interviews. The short telephone questionnaire included a validation component that asked for details about the respondents' original round 4 interviews (e.g., duration, mode) and information on whether or not they were paid for their participation. The reinterview component involved re-asking questions that were drawn directly from the youth interview. This component included some characteristics of their current residence, several expectations questions, a question about weekly family activities, and two questions concerning the respondent's income from the previous year. Finally, respondents were asked whether the interviewer they had in round 4 was the same one who conducted their interview in round 3.
Round 5. Between November 2001 and June 2002, 1,036 respondents completed validation reinterviews for round 5. This produced an overall project validation rate of 13.1 percent of completed interviews. Re-interview questions included marital status, current employer name and start date, three child-care questions (if female and born in 1983-84), and the respondent's total income from the previous year. Respondents also were asked whether the interviewer they had in round 5 was the same one who conducted their interview in round 4. Finally, new in round 5 was the addition of a question that asked respondents why they completed the interview.
Round 6. Between November 2002 and June 2003, 876 respondents completed validation reinterviews for round 6. This produced an overall project validation rate of 11.1 percent of completed interviews. The reinterview component involved re-asking questions that were drawn directly from the youth interview. This component included the number of people in the household, current employer name and type of employer (government, private, non-profit, family business), if the respondent was in the Armed Forces, the number of illnesses or injuries in the last 12 months, if a close relative had died in the past 5 years, if the respondent had ever received food stamps, and the respondent's total income from wage/salary from the previous year. Respondents also were asked whether the interviewer they had in round 6 was the same one who conducted their interview in round 5. In addition, respondents were asked why they completed the interview.
Round 7. Between October 2003 and July 2004, 1,145 respondents completed validation reinterviews for round 7. This produced an overall project validation rate of 14.8 percent of completed interviews. The short telephone questionnaire included the length of the re-interview, mode of interview, number of sessions it took to complete the interview, whether the respondent received payment for the interview and if so, the amount of the payment, the number of people in the household, highest grade attended, if respondents had lived on their own, if the respondent received unemployment compensation benefits, the number of illnesses or injuries in the last 12 months, the respondent's total income from wage/salary from the previous year, whether the same interviewer conducted the prior interview, and if the respondent read any materials provided by NORC.
Round 8. Between November 2004 and July 2005, 934 respondents completed validation reinterviews for round 8, for an overall project validation rate of 12.4% of completed interviews. This component included the questions mentioned above for round 7 except the question about living on one's own; it also included a question about whether the respondent had registered to vote in the November 2004 election.
Round 9. Between November 2005 and August 2006, 1080 respondents completed validation reinterviews for round 9, for an overall project validation rate of 14.7% of completed interviews. This component included questions about the length of the re-interview, mode of interview, use of a laptop during the interview, number of sessions needed to complete the interview, incentive details, number of household members, highest grade attended, if respondent received unemployment compensation benefits, marital status, number of illnesses or injuries in the last 12 months, respondent's total income from wage/salary from the previous year, whether the same interviewer had conducted the prior interview, and what methods the project had used to contact the respondent.
Round 10. Between November 2006 and July 2007, 1226 respondents completed validation reinterviews for round 10, for an overall project validation rate of 16.2% of completed interviews. The validation reinterviews usually lasted about five minutes. This component included questions about the length of the main interview, mode of the main interview, use of a laptop during the interview and other administration details, number of sessions needed to complete the interview, incentive detail, number of household members, unemployment compensation benefits, highest grade attended, marital status, number of illnesses or injuries in the last 12 months, respondent's total income from wage/salary from the previous year, whether the same interviewer had conducted the prior interview, methods of contacting the respondent, respondent's opinions regarding the topics of the main questionnaire, and an opportunity for the respondent to ask questions about the study.
Rounds 11 and up. Starting in round 11, validation variables were not released to public.