Nonresponse bias analysis using reluctant respondents who responded after receiving monetary incentives

As survey researchers attempt to maintain traditionally high response rates, reluctant respondents have resulted in increasing data collection costs. This respondent reluctance may be related to the amount of time it takes to complete an interview in large-scale, multi-purpose surveys, such as the National Survey of Recent College Graduates (NSRCG). Recognizing that respondent burden or questionnaire length may contribute to lower response rates, in 2003, following several months of data collection under the standard data collection protocol, the NSRCG offered its nonrespondents monetary incentives about two months before the end of the data collection,. In conjunction with the incentive offer, the NSRCG also offered persistent nonrespondents an opportunity to complete a much-abbreviated interview consisting of a few critical items. The late respondents who completed the interviews as the result of the incentive and critical items-only questionnaire offers may provide some insight into the issue of nonresponse bias and the likelihood that such interviewees would have remained survey nonrespondents if these refusal conversion efforts had not been made.

In this paper, we define "reluctant respondents" as those who responded to the survey only after extra efforts were made beyond the ones initially planned in the standard data collection protocol. Specifically, reluctant respondents in the 2003 NSRCG are those who responded to the regular or shortened questionnaire following the incentive offer. Our conjecture was that the behavior of the reluctant respondents would be more like that of nonrespondents than of respondents to the surveys. This paper describes an investigation of reluctant respondents and the extent to which they are different from regular respondents. We compare different response groups on several key survey estimates. This comparison will expand our understanding of nonresponse bias in the NSRCG, and of the characteristics of nonrespondents themselves, thus providing a basis for changes in the NSRCG weighting system or estimation procedures in the future.