Use of monetary and nonmonetary incentives to increase response rates among African Americans in the Wisconsin Pregnancy Risk Assessment Monitoring System.

From 2009 to 2010, an experiment was conducted to increase response rates among African American mothers in the Wisconsin Pregnancy Risk Assessment Monitoring System (PRAMS). Sample members were randomly assigned to groups that received a prepaid, cash incentive of $5 (n = 219); a coupon for diapers valued at $6 (n = 210); or no incentive (n = 209). Incentives were included with the questionnaire, which was mailed to respondents. We examined the effects of the incentives on several outcomes, including response rates, cost effectiveness, survey response distributions, and item nonresponse. Response rates were significantly higher for the cash group than for the coupon (42.5 vs. 32.4%, P < .05) or no incentive group (42.5 vs. 30.1%, P < .01); the coupon and no incentive groups performed similarly. While absolute costs were the highest for the cash group, the cost per completed survey was the lowest. The incentives had limited effects on response distributions for specific survey questions. Although respondents completing the survey by mail in the cash and coupon groups exhibited a trend toward being less likely to have missing data, the effect was not significant. Compared to a coupon or no incentive, a small cash incentive significantly improved response rates and was cost effective among African American respondents in Wisconsin PRAMS. Incentives had only limited effects, however, on survey response distributions, and no significant effects on item nonresponse.