A comparison of small monetary incentives to convert survey non-respondents: a randomized control trial

BMC Medical Research Methodology

Melissa R Partin³  Siamak Noorbaloochi³  Joseph P Grill²  John Stevenson¹  Erin Hulbert²  Alisha Baines Simon²  Joan M Griffin³ 

[1]University of Wisconsin Survey Center, University of Wisconsin, Sterling Hall, 475 N. Charter St. Madison, WI 53706-1582, USA

[2]Center for Chronic Disease Outcomes Research (CCDOR), Minneapolis VA Health System, One Veterans Drive, Minneapolis, MN 55417, USA

[3]Department of Medicine, University of Minnesota Medical School, 420 Delaware Street SE, MMC 194, Suite 14-110 Phillips-Wangensteen Bldg, Minneapolis, Minnesota 55455, USA

关键词: non-response;    response rate;    financial incentives;    incremental cost-effectiveness ratios;    data collection;    Cost-effectiveness;   

Others  :  1140194
DOI  :  10.1186/1471-2288-11-81

 received in 2011-01-19, accepted in 2011-05-26,  发布年份 2011

【 摘 要 】

Background

Maximizing response rates is critically important in order to provide the most generalizable and unbiased research results. High response rates reduce the chance of respondents being systematically different from non-respondents, and thus, reduce the risk of results not truly reflecting the study population. Monetary incentives are often used to improve response rates, but little is known about whether larger incentives improve response rates in those who previously have been unenthusiastic about participating in research. In this study we compared the response rates and cost-effectiveness of a $5 versus $2 monetary incentive accompanying a short survey mailed to patients who did not respond or refused to participate in research study with a face-to-face survey.

Methods

1,328 non-responders were randomly assigned to receive $5 or $2 and a short, 10-question survey by mail. Reminder postcards were sent to everyone; those not returning the survey were sent a second survey without incentive. Overall response rates, response rates by incentive condition, and odds of responding to the larger incentive were calculated. Total costs (materials, postage, and labor) and incremental cost-effectiveness ratios were also calculated and compared by incentive condition.

Results

After the first mailing, the response rate within the $5 group was significantly higher (57.8% vs. 47.7%, p < .001); after the second mailing, the difference narrowed by 80%, resulting in a non-significant difference in cumulative rates between the $5 and $2 groups (67.3% vs. 65.4%, respectively, p = .47). Regardless of incentive or number of contacts, respondents were significantly more likely to be male, white, married, and 50-75 years old. Total costs were higher with the larger versus smaller incentive ($13.77 versus $9.95 per completed survey).

Conclusions

A $5 incentive provides a significantly higher response rate than a $2 incentive if only one survey mailing is used but not if two survey mailings are used.

【 授权许可】

   
2011 Griffin et al; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

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