Combining conditional and unconditional recruitment incentives could facilitate telephone tracing in surveys of postpartum women

Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA.
Journal of Clinical Epidemiology (Impact Factor: 3.42). 08/2006; 59(7):732-8. DOI: 10.1016/j.jclinepi.2005.11.011
Source: PubMed


To compare tracing and contact rates using alternative incentives in a computer-assisted telephone interview (CATI) survey among postpartum women.
In a randomized trial of 1,061 postpartum women 18-49 years of age selected from four Iowa counties, we compared the effects of: (1) unconditional $5 telephone card incentive enclosed with the introductory letter followed by $25 incentive conditional upon successful telephone tracing, contact, and completion of CATI (Group 1, n = 530) vs. (2) $30 incentive conditional upon subject completion of CATI (Group 2, n = 531).
Overall telephone tracing and contact rates achieved were 67.8% and 66.6%, respectively. Tracing (70.2 vs. 65.4%, P = .09) and contact (68.5 vs. 64.8%, P = .26) rates were consistently higher among subjects assigned the combination of a conditional and an unconditional incentive. The combined incentive type had a greater impact on telephone tracing success rates for subjects on whom we could not initially locate an active telephone number (16.7 vs. 7.3%, P = .07) when compared to subjects for whom we found an active telephone number at the time of mailing the introductory letter (78.9 vs. 75.9%, P = .30).
Combining conditional and unconditional recruitment incentives can facilitate telephone tracing efforts in surveys conducted among recently postpartum women.

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    • "Some studies have specifically examined the use of incentives in low income or high minority populations [1,3,4,17-19]. Unconditional incentives, which are prepaid and not conditional upon participation, have been shown to be more effective than conditional incentives, [9,14,16,20-22] particularly in minority and low income populations [1,3,17-19]. However, no studies have examined the effect of unconditional incentives in Canadian lower socioeconomic status, lower education and immigrant populations in a telephone survey. "
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