Differential Effects of Incentives on Response Error, Response Rate, and Reliability of a Mailed Questionnaire

This study investigated some of the issues associated with stimulating increased return rates to a mail questionnaire among school counselors. Specifically studied were (a) the effects of the number of incentives on response rates, (b) response error associated with increasing the number of incentives, and (c) the impact of receiving incentives on the reliability of the Counselor Function Inventory (CFI). The response rates were analyzed using a linear trend test for proportions. The results show that as the number of incentives received increased, the return rates increased in a linear fashion. The incentives did not introduce response error or affect the reliability of the CFI for the samples under study.