The tea bag experiment: more evidence on incentives in mail surveys

This paper reports the results of a study which compared the effectiveness of a tea bag and a $1 coin as prepaid Incentives in a mail survey of the ge neral public. The tea bag had no effect on response rate but the dollar coi n produced a significant increase in response of more than 7%, confiming th e efficacy of this type of incentive. The paper points out that it is impos sible to generalise about the cost-effectiveness of prepaid monetary incent ives, except to say that they are most cost effective when questionnaire, s tationery and postage costs are high and labour costs are low. However, if a no-incentive response rate is acceptable for a mail survey, a small prepa id incentive with one reminder letter is the most cost effective way of spe nding a limited research budget.