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 X-2 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. 2008 Elsevier Inc. All rights reserved.