Objective: The purpose of this study was to characterize the response rates of mail surveys published in medical journals; determine how the response rate varies among subjects who are typical targets of mail surveys; and assess the contribution of various techniques used by researchers to improve response rates.
Methods: One hundred and seventy-eight manuscripts published in 1991, representing 321 separate mail surveys, were abstracted to determine response rates and survey techniques. in a follow-up mail survey, 113 authors of these manuscripts provided supplemental information.
Results: The average response rate among mail surveys published in medical journals is approximately 60%. however, response rates vary depending on the topic studied and the techniques used. published surveys of physicians have a median response rate of only 54%, and those of non-physicians have a median response rate of 68%. furthermore, multivariate models suggest that written reminders provided with a copy of the instrument and telephone reminders are associated with 13% higher response rates than surveys that do not use these techniques. other techniques, such as anonymity and financial incentives, are not associated with higher response rates.
Conclusions: Although several mail survey techniques are associated with higher response rates, response rates to published mail surveys tend to be modest. however, the response rate of a survey is, at best, an indirect indication of the extent of non-response bias. researchers, journal editors, and readers should pay more attention to bias assessments and less to specific response rate thresholds.