COST-EFFECTIVENESS OF FOLLOW-UP STRATEGIES IN IMPROVING THE RESPONSE RATE OF MAIL SURVEYS

Although inexpensive and geographically flexible, mail surveys typical ly result in low response rates. These low response rates can bias the results when nonrespondents differ systematically from respondents. B ecause follow-lips with nonrespondents have been shown to increase ove rall response rate, the purpose of the study was to compare both respo nse rate and cost-effectiveness ratio of four different follow-up stra tegies. Nonrespondents from a national mailing of 596 surveys were ran domly assigned into four strategy conditions: (1) postcard reminders; (2) second mailings; (3) telephone reminders; and (4) Dillman's multip le follow-up strategy, which combines all three. When telephone number s were not available, the Dillman strategy and second mailings yielded significantly higher return rates than the telephone condition. Howev er, it was determined if telephone numbers had been available, there w ould be no significant differences among response rates for the four f ollow-up conditions. In both situations, postcard re minders 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 r esponse rate. (C) 1998 Elsevier Science Inc.