Black Art Posters, A Low-Cost Incentive to Increase Cohort Study Enrollment among Blacks

Abstract

To improve enrollment and questionnaire return rates among black Adventists, we offered black art posters ($5 each for reproduction and mailing) as an alternative or in addition to the standard $10 incentive for questionnaire completion in a longitudinal cohort study. 57 churches located in one US region were offered the art or $10. 20 churches were subsequently offered both art and $10. 24 churches in the same region launching recruitment during alternate months of the same year comprised the control group. The primary outcome measures were study enrollment rates (questionnaires requested) and questionnaire return rates as a proportion of each church’s goal. 9.3% of participants offered art as an alternative selected art in preference to $10. Half of participants offered both incentives indicated a poster selection. Crude questionnaire return rates were 58.4% for the intervention churches and 40.4% for the control churches. Controlling for income and other covariates, questionnaire requests per church goal among intervention churches offered the art posters or $10 was similar to that of controls. However, response rates among those offered both the art and $10 were significantly higher (p ? 0.02). Survey return rates per goal were higher in the churches offered both incentives, but this increment did not quite reach statistical significance (p ¼ 0.09). Conclusions: These data suggest that the art incentive improved study enrollment and possibly survey return rates at a modest cost. The relatively low rate of poster selection as an incentive indicates that the art primarily influenced participation rates indirectly, by creating a more culturally inclusive image of the study, and, secondarily, directly, as an appealing incentive.