Cash prizes and mail survey response rates: A threshold analysis

In a study involving the mailing of some 3,150 questionnaires, the ability of six kinds of incentives to augment survey responses was tested against a no-incentive control condition. Two of the incentives were small prepaid monetary amounts (25¢ and $1.00), while the remaining four consisted of the opportunity for respondents to win cash prizes valued at either $50, $100, $150, or $200. The use of such cash prizes enabled an approximate test of the just-noticeable-difference principle in terms of both its absolute and differential threshold hypotheses. The 25¢ and $1.00 incentives yielded response rates that were significantly larger than that of the control group. No confirmation of the differential threshold hypothesis was evidenced, at least over the range of cash prizes employed in the present study. In contrast, the absolute threshold hypothesis received support. Suggestions for further research in this area were also identified.