Increasing response rates for mailed surveys of Medicaid clients and otherlow-income populations

Mailing surveys to low-income populations is often avoided because of conce rn about low response rates. In this study, the authors used a mailed surve y of a low-income population to test whether $1.00 or $2.00 cash-response i ncentives were worth the expense and whether 2-day priority mail ($2.90 pos tage) would yield a sufficiently higher response rate than certified mail ( $1.52 postage) to justify its cost. In 1994, 2,243 randomly selected famili es in subsidized health care programs in Pierce County, Washington, were ra ndomly sent no incentive, $1.00, or $2.00 in the first of three mailings. F or the third mailing, nonrespondents were randomly assigned to receive eith er certified or 2-day priority mail. After 4 weeks, the response rates were 36.7%, 48.1%, and 50.3% for the no-incentive, $1.00, and $2.00 groups, res pectively. After three mailings, the cost per response was the lowest for t he group that received $1.00. The response rate for the certified mailing ( 28.1%) was significantly higher than the rate for the more expensive priori ty mailing (21.7%). No incentive-related bias was detected. The authors con cluded that the most efficient protocol for this low-income population was to use a $1.00 incentive in the first mailing and a certified third mailing .