Collecting high quality data in surveys of students and low-income populations is critical for many studies in social science. Research indicates small, monetary pre-incentives are most effective in increasing response rates; less effective are post-incentives and lotteries, which are offered contingent upon completion of the survey. However, little is known about the effectiveness of large cash post-incentives relative to lotteries for cash or gifts. Moreover, given growing constraints on research funds, research is needed to determine which types of incentives are most cost-effective. In this study we consider the effectiveness of various types of post-incentives with a low-income population: college students receiving Pell Grants (a federal means tested form of financial aid). In particular, we assess responsiveness to a cash post-incentive relative to lotteries offering monetary or nonmonetary incentives. A stratified random sample of Pell Grant recipients that were initially enrolled in Wisconsin public higher education in 2008 (N=3,000) and surveyed in their first semester, then followed over time whether they remained enrolled in school or not. All panel members were initially mailed a $5 cash pre-incentive and invitation to complete a web survey in 2011. Nonresponders received up to three email reminders and then sent a mail SAQ. Respondents were randomly assigned to the following post-incentive groups:
• Condition 1: no post-incentive
• Condition 2: $10 post-incentive
• Condition 3: inclusion in a lottery for $50 (paid out to 25 winners)
• Condition 4: inclusion in a lottery for an iPad
The analysis includes:
• Effects of the experimental treatments on unit and item nonresponse.
• Effects of incentives on nonresponse bias, looking at survey reports, reported civic engagement and linked administrative data
• Differences in participation across incentive groups looking at past participation for this study.
• Analysis of cost variation among the treatments.