Response Rate Stimulants in Mail Surveys: A Potential Source of Sample Composition Bias

Abstract

Users of mail surveys are continually searching for ways to increase response rates without adversely affecting total survey costs, but it is possible that higher response rates are sometimes achieved at the cost of decreased quality of response and/or increased sample bias. This paper studies return envelope style as a response stimulant. While recognizing the trade-offs between higher response rates for stamped return envelopes and lower total costs for business reply return envelopes, this study asks if response quality and sample composition are affected. Response quality was not differentially affected by return envelope style. However, an important difference in the age composition of the different groups of respondents was detected. It appears that the middle categories of age (41–ars) may resist returning questionnaires in business reply return envelopes to a greater extent than in stamped return envelopes. More research on this question is needed. No differences in sex, marital status, occupation, education or income were detected.