The workshop for which this chapter was prepared is focused specifically on collecting better data from low-income and welfare populations, and one of the clear challenges associated with surveying such populations is how to achieve high enough levels of participation to minimize bias due to nonresponse. Increasingly, respondent incentives have been proposed as a valuable tool in achieving this goal. Thus, the basic question addressed in this chapter is whether the payment of respondent incentives is indeed an effective means of reducing non-response, both for surveys in general and, especially, in surveys conducted with low-income and welfare populations.
As noted in the paper, a substantial research literature consistently has demonstrated the value of incentive payments to survey respondents for increasing cooperation and improving speed and quality of response in a broad range of data collection efforts, most notably in mail surveys. Because mail surveys are of limited utility in studies of welfare reform or low-income populations, experiments involving the use of incentives in face-to-face or telephone interviews are of greatest relevance to answering this basic question. These experiments are more recent in vintage, sparser in coverage, and not entirely consistent in their findings.(12)
Thus, although it is tempting to generalize from the findings presented here, it is important to note that many of the results are based on only a few studies and may not apply to other populations or situations, including especially those of particular interest here (i.e., surveys of low-income and welfare populations on questions related to welfare reform). Thus, if at all possible, we urge pretesting of the particular incentive plan proposed with the population targeted by ones survey and the instrumentation and other survey methods to be employed, rather than relying exclusively on this research literature.
Nevertheless, with these cautions, a few basic conclusions, guidelines, and recommendations can be gleaned from the evidence accumulated to date:
- Consistent with an extensive literature on the use of incentives with mail surveys, prepaid monetary incentives seem to be useful in recruiting low-income and minority respondents into interviewer-mediated surveys, even when the burden imposed on participants is relatively low. The use of incentives probably should be part of the design and strategy for all such surveys. However, they should not be used as substitutes for other best-practice persuasion strategies designed to increase participation, such as explanatory advance letters, endorsements by people or organizations important to the population being surveyed, assurances of confidentiality, and so on.
- How much money to offer respondents in these circumstances is not at all clear from the evidence currently available. Less money appears to be needed to recruit lower income respondents into a survey than those with higher incomes, but the optimal amount likely will depend on factors such as the length of the interview and the salience of the topic, and may also change over time. To determine the appropriate incentive amount for a given study, we reiterate our prior admonition that there is no real substitute for a careful pretest of various incentive amounts within the specific population and design context proposed for a given survey.
- Although it is tempting to speculate on this issue, and we often have been asked to venture an educated guess on what an appropriate range might be for incentives in studies of welfare and low-income populations, we believe that doing so would not be prudent for a number of reasons. In particular, as we have noted, the experimental literature that provides evidence directly relevant to this question is relatively sparse, idiosyncratic, and inconsistent, and the dynamics associated with providing incentives to these populations quite likely are both fluid and in large part specific to location, economy, and even cultural factors.
As a general guideline, the Office of Management and Budget (OMB) has most recently approved the use of respondent incentives in the $20-$30 range based on empirical experimental tests conducted with specific target populations similar to those of interest here, but incentive amounts both higher and lower than these also have been approved and successfully implemented.
- Prepaid respondent incentives are especially important in panel surveys (a design favored by many studies of low-income populations and studies of welfare reform because of the questions of particular interest in such studies) because of the critical need to recruit a high proportion of the eligible population into the initial round of measurement. When it is possible to send payment in advance to at least a portion of the sample, the amount of cash interviewers must carry with them is reduced. Although such concerns have not been systematically validated either empirically or by anecdotal evidence from survey practitioners (see Kulka, 1995), the potential for putting either respondents or interviewers at increased risk of crime through the use of incentives is at least partially offset by this approach, along with accruing the well-established benefits of prepayment.
- For a number of practical reasons, including restrictions on the use of state and federal monies to compensate survey participants (especially those receiving state aid), the use of lotteries as an incentive strategy has considerable appeal. However, lotteries rather consistently appear to be less effective than individual prepaid incentives in stimulating survey response.
- It is possible that the use of prepaid incentives will change responses to at least some questions by affecting a respondents mood (i.e., making the respondent more optimistic about the surveys content). Although evidence of this phenomenon is mixed, it is worth evaluating this possibility empirically through an experiment whenever it is feasible to do so.
- Although the use of incentives strictly or primarily for refusal conversion is fairly widespread in current survey practice, incentives should be used sparingly as a refusal conversion technique. Respondents regard this practice as unfair or inequitable, although there is no evidence that such differential payments reduce future willingness to participate in surveys, including termination of payments in subsequent waves of a panel survey in which an incentive was previously provided. However, there are suggestions that the routine use of refusal conversion payments may condition interviewers to expect (and depend on) them, and that this may have a negative impact on overall interviewer performance.
- Finally, several issues broadly related to the protection of human subjects are sometimes raised in connection with using respondent incentives. First, specific to welfare populations is the issue of whether incentives count against the value of benefits received. Although the legislative and regulatory bases for such restrictions vary by state, and there is at least anecdotal evidence that some states have been reluctant to authorize the use of incentives in their surveys for this reason, such restrictions do not yet appear to be widespread, and researchers and officials in some states have indicated that such restrictions can be waived by the state in any case.
Second, it is well known that the OMB has had a longstanding policy that has strongly discouraged the use of incentives in federal statistical surveys. Although these policies are currently in review, recent drafts of OMBs Implementing Guidance prepared to support the Paperwork Reduction Act of 1995 provide more specific guidelines to federal agencies on the use of incentives, when incentives might be justified, and the types of documentation or evidence required to support a request for incentives. Specifically, these guidelines make clear that: (1) incentives are not intended to pay respondents for their time; (2) noncash or monetary incentives of modest size ($20-$30) are preferred; and (3) one must demonstrate empirically that such payments will significantly increase response rates (and the resulting reliability and validity of the study), although the potential need for and efficacy of incentives for certain purposes and circumstances is clearly acknowledged.
Third, some welfare reform researchers have noted a recent and potentially growing problem with Institutional Review Boards (IRBs), some of which have argued that the use of incentives (especially large incentives) may be regarded as coercive, especially among low-income respondents, thereby posing a credible threat to truly informed consent. That is, having been offered (or paid) an incentive to participate in a study, potential respondents feel they cannot really refuse, even if they are reluctant to do so for other reasons. Although assessing this potential human subject threat is clearly within the purview of IRB review, most incentive payments used to date have in fact been fairly modest in size. These are often characterized as tokens of appreciation rather than compensation for time spent. Most IRBs to date have determined that these token incentives are not so large as to constitute coercion, provided that such incentives are not cited as part of informed consent or as one of the benefits of participation in the study.
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