Warning that reminders will be sent increased response rate

Abstract

In 1993 a postal survey was undertaken of obstetricians views of prenatal screening and diagnosis. Every other letter despatched contained a postscript which stated “Because a good response rate is so important, we will be sending reminders to non-respondents. To avoid this irritant, why not fill it in now and get it over with?!”. The hypothesis was that this would increase the response rate and reduce the need for reminders. The hypothesis was supported. If we assume that the response rate for those who did not have the postscript is what we would have achieved for the whole sample otherwise, then the use of this stratagem resulted in a 19% reduction in the number of first reminders needed, with a consequent reduction in costs (in this case approximately £15).