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Published on: September 19, 2012
The effect of conducting a lottery on questionnaire response rates: a randomised controlled trial
Mette Aadahl1, Torben Jørgensen
1Research Centre for Prevention and Health, Glostrup University Hospital, Copenhagen Country, Glostrup, Denmark. meaa@glostruphosp.kbhamt.dk
Aim:
To study the effect of a lottery incentive on questionnaire response rate.
Material And Methods:
In Copenhagen County, Denmark, a random sample of 2543 men and women between the ages of 19 and 60 were randomised into a control group and an intervention group. Both groups were contacted by mail and asked to complete a questionnaire on sociodemografic characteristics, self-rated health and self-reported physical activity level. The intervention group was offered participation in a small lottery for returning the questionnaire. No incentive was offered to the control group.
Main Results:
The final response rate for the control group was 60.4 and 63.4% for the intervention group. Although the response rate was significantly higher in the intervention group after 2 and 3 weeks, the difference in the final response rate between groups was not statistically significant (p = 0.12). There was no statistically significant difference between groups in sociodemografic characteristics, self-rated health or self-reported physical activity level.
Conclusion:
A lottery incentive had no significant effect on the overall response rate, but may have contributed to a quicker response. Furthermore a lottery incentive did not seem to alter the selection of respondents.
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