Lottery incentives did not improve response rate to a mailed survey: a randomized controlled trial.

OBJECTIVES Our study aimed to examine the effect of an instant lottery ticket incentive on the response rate to a mailed questionnaire in a population of trauma patients. STUDY DESIGN AND SETTING A randomized controlled trial at a major trauma center with 728 patients randomized into 2 groups prior to mailing of a questionnaire. One group of patients (Group A) had a sentence inserted into the cover letter stating that they would receive a $4 instant lottery ticket upon receipt of a completed questionnaire; Group B did not have an incentive. The response rate for both groups was measured after the initial mailing and at the end of the study. The results were analyzed using the X2 test to compare 2 proportions and a P value of .05 was considered significant. RESULTS The early response rate in Group A was lower than in Group B, and the response rates for both groups were similar at final follow-up. The differences at both time periods were not statistically significant. CONCLUSION The use of an instant lottery ticket incentive did not improve the response rate to a mailed questionnaire.