The Effect of Monetary Incentives and Follow-Up Mailings on the Response Rate and Response Quality in Mail Surveys

The joint and comparative effects of the use of monetary incentives and follow-up mailings were examined in a mail survey of suburban Washington, DC cable television subscribers. Four experimental groups received monetary incentives enclosed with the first mailing only (0. 25, 0. 50, 1. 00, or 2. 00) and three follow-up mailings. These groups were compared with each other and against a control group that did not receive an incentive. The results indicated that the response rate from the first mailing increased significantly as the incentive amount increased from zero to 0. 25, and from 0. 25 to 1. 00. Four mailings without an incentive produced a higher response rate than a single mailing with an incentive, but a combination of follow-up mailings and a 1. 00 or 2. 00 incentive produced a significantly higher response rate than an equivalent number of mailings without an incentive. There was some evidence of intertreatment response bias. Larger monetary incentives tended to produce: (1) a greater degree of effort expended in completing the questionnaires, as measured by the number of short answers and comments provided, and the number of words written, and (2) comments that were more favorable toward the survey sponsor.