Prepaid vs. Promised Monetary Incentives to Questionnaire Response: Further Evidence
In: Public opinion quarterly: journal of the American Association for Public Opinion Research, Band 40, Heft 1, S. 105-107
ISSN: 0033-362X
While the effect of prepaid, overpromised monetary incentives appear stronger, not all research situations allow prepayment of cash inducements. The results are reported of a study that tested the promised incentive rates of $1, $2, $3, & $5 as well as no incentive. Drivers of 900 randomly-selected automobiles were approached as they stopped at a turnpike toll gate & handed a postage-paid return envelope containing a cover letter, a 10-page questionnaire &, in some packets, a sheet promising a cash incentive for questionnaire completion. Envelopes testing no incentive logically contained no incentive sheet. The different incentive values were randomly distributed. The promised incentive values of $2 with a response rate of 41% resulted in a appreciable increase in response over lower values & represents a statistically significant difference from the $1 cash incentive with a 25% response rate, & from offering no incentive which resulted in a 28% response rate. The incentive value of $0 & $1 are not significantly different & similarly no significant differences are seen between $2 & $3 (40.5% response rate) & between $3 & 1225 (44% response rate). $2 appeared to be the most effective promised monetary incentive rate. 1.