In an effort to counter the problem of noncooperation, survey organizations are offering incentives to respondents with increasing frequency, some at the outset of the survey, as has traditionally been done in mail surveys, and some only after the person has refused, in an attempt to convert the refusal. This article reports on a series of experiments carried out over a period of about 2 years with a monthly telephone survey, the Survey of Consumer Attitudes, in an effort to increase response rates or reduce interviewer effort. We report on experiments with prepaid versus promised incentives; advance letters; and advance letters with prepaid incentives; and we also report on the effects of incentives on response quality, sample composition, response bias, interviewer and respondent expectations, and costs.