Cost-Effectiveness of Follow-Up Strategies in Improving the Response Rate of Mail Surveys

Abstract Although inexpensive and geographically flexible, mail surveys typically result in low response rates. These low response rates can bias the results when nonrespondents differ systematically from respondents. Because follow-ups with nonrespondents have been shown to increase overall response rate, the purpose of the study was to compare both response rate and cost-effectiveness ratio of four different follow-up strategies. Nonrespondents from a national mailing of 596 surveys were randomly assigned into four strategy conditions: (1) postcard reminders; (2) second mailings; (3) telephone reminders; and (4) Dillman’s multiple follow-up strategy, which combines all three. When telephone numbers were not available, the Dillman strategy and second mailings yielded significantly higher return rates than the telephone condition. However, it was determined if telephone numbers had been available, there would be no significant differences among response rates for the four follow-up conditions. In both situations, postcard reminders were most cost-effective. Thus, although surveys with higher response rates are generally accorded greater validity, the additional cost and time of the multiple follow-ups do not always lead to a significantly higher response rate.