Abstract
From many previous studies, we have learned that sending a $2 bill in an invitation letter to participate in health research increases the likelihood of participation. In the Guide to Decide Study, thousands of women were invited to log on to a Web site to answer a baseline questionnaire, and they were mailed $10 as a thank you when it was complete. Most of the women were exposed to a decision aid that gave them risk information about using tamoxifen or raloxifene as a prophylactic for women with increased risk for breast cancer, and they were asked to return to the Web site 3 months later to complete a follow-up survey. A control group of women were promised access to the decision aid if they returned to the Web site to complete a follow-up survey 3 months after enrollment. One theory would suggest that women who received access to the decision aid at baseline would be more engaged and therefore more likely to return to the Web site to complete the 3-month follow-up questionnaire. Another theory would suggest that women who were not given access to the decision aid would be most inclined to return after 3 months to do so. This poster will illustrate whether there is a difference between a $2 and $5 pre-incentive when mailed in a letter to participants inviting them back to answer survey questions 3 months following their enrollment. Further, we will test whether the amount of the pre-incentive and the corresponding response rates differ between the intervention group and the control group.
- Received September 11, 2008.
