CHARITIES, NO; LOTTERIES, NO; CASH, YES: MAIN EFFECTS AND INTERACTIONS IN A CANADIAN INCENTIVES EXPERIMENT

The effects on response rates to mail surveys of prepaymentcash incentives, charitable donations, and the chance to wina lottery prize are examined in a true experimental design.A survey on environmental issues was conducted during the fallof 1994 among 3,088 households drawn from the Grand River watershedregion of southwestern Ontario, Canada. The 20-cell incentivesexperiment crossed three levels of prepaid monetary cash incentive($2, $5, and $10) with a control group (no cash incentive),plus the offer to make a charitable donation ranging from $2to $10 on behalf of the respondent, or participation in a lotteryfor prizes of $200. The overall response rate to the survey,with three follow-ups, was 70.7 percent with the effects ofthe prepaid cash rewards demonstrated, but not those for thelottery or charitable donations. Logistic regression analysisof response rate supports a main effects model for cash incentivesbut does not support either of two alternative models for maineffects of the lottery and charitable donations or interactions.Further analysis demonstrates a pattern of earlier responseas a result of prepaid incentives. The findings are discussedin terms of their cost-benefit implications and with respectto conceptualizations of respondents' motives for completingmail questionnaires.