Methodological Research on Incentives

Appendix SS

Methodological Research on Incentives

Providing incentives

Achieving high recruitment and retention rates is critical to data quality. Providing an extrinsic incentive can improve these rates, especially in populations defined as being in poverty;^1,2 and a monetary incentive even more so.³ In addition, improved cooperation rates reduce the need for call backs which decrease survey costs⁴ and disproportionately encourage those less interested in the research to participate, thus reducing non-response bias.⁵ Finally, the research suggests that individuals receiving an incentive are more co-operative in providing contact information that will allow tracking their whereabouts for successive rounds of a survey.⁶ Based on this research, WIC participants in the ITFPS-2 will receive a monetary incentive after completing enrollment and for each data collection event in the study: $50 for enrollment and $20 for the 11 follow-up interviews (prenatal, 1-month, 3-month., 5-month, 7-month, 11-month, 13-month, 15-month, 18-month, and 24 month). In addition, we will compensate them $10 per interview for using their cellphone to complete an interview, and an additional $20 if they are selected to complete a 2^nd 24-hour dietary recall AMPM interview. Finally, participants who drop out of WIC will be paid $20 to have research staff measure their child’s length and weight. Compensation could be a total of $400 over the 2 years they are in the study.

No incentive payments are planned for State and Local WIC administrators or WIC site staff for their involvement in the ITFPS-2. Participating State and Local agencies will sign an agreement with Westat that describes the responsibilities and benefits they will receive for participation. Further, no incentive payments are planned for data managers in hospitals and health care provider clinics since providing health data is part of their job responsibilities.

1Singer E. (2002). The use of incentives to reduce non response in households surveys in: Groves R, Dillman D, Eltinge J, Little R (eds) Survey Non Response. New York: Wiley, pp 163-177.

2James T. (1996). Results of wave 1 incentive experiment in the 1996 survey of income and program participation. Proceedings of the Survey Research Section, American Statistical Association, 834-839.

3Groves R, Fowler F, Couper M, Lepkowski J, Singer E. (2009) in: Survey methodology. John Wiley & Sons, pp 205-206.

4Berlin, M., Mohadjer, L., Waksberg, J., Kolstad, A., Kirsch, D., Rock, D., and Yamamoto, K. (1993). An experiment in monetary incentives. Proceedings of Survey Research Methods Section of American Statistical Association, 393-8.

5Groves, R., Singer, E., Corning, A. (2000). Leverage-saliency theory of survey participation: description and an illustration. Public Opinion Quarterly. 64(3): 299-308.

6Shettle C, Mooney G. (1999). Monetary incentives in US Government surveys. Journal of Official Statistics, 15(2): 231-250.

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