because they want to minimize the risk of expulsion from the program or other potential negative consequences. This is known as “social desirability bias.” There is some evidence from undergraduate students in the United States that self-reports of alcohol consumption can be biased downward (David, Thake and Vilhena 2010). In developing contexts, this is much less explored for alcohol and tobacco consumption. (For sexual behaviors, it has been explored extensively.<sup>7</sup> ) However, we do not expect this to be a major problem here, for the following reasons. First, the impact estimates presented here are usually based on detailed expenditure surveys that ask a household respondent how much the household spends on each of a long list of items. Alcohol and tobacco are not singled out. For the estimates of what proportion of households spent any resources on temptation goods, alcohol and tobacco may be singled out, which could explain why several studies found zero reports of any spending on temptation goods. However, those estimates merely provide supportive evidence to the more robust impact estimates.

Second, transfer income is not asked about separately, so households would have to recall the amount of their overall income spent on temptation goods before the program and report a similar amount later. The simplest solution for households seeking to appease an interviewer would be to report zero or extremely low expenditures on alcohol and tobacco. This is especially true since household surveys are administered infrequently and so recalling previous reports may be difficult. In that case, we would expect to see a much starker pattern of significant negative impacts. On the contrary, we observe just 24% of all impacts on expenditures to be negative and significant, and 9% for randomized-control trials. The far more common result is an insignificant difference: the outcome in all eleven randomized trials (Figure 2 Panel D). This does not look like systematic social desirability bias.

An additional concern could be that these studies were not sufficiently statistically powered to capture consumption impacts at all, whether on temptation goods or other categories of consumables. For this, we focus on the 6 positive and insignificant estimates in more detail. These 6 estimates come from 5 studies (each from different countries around the world), most of which report the estimated impact of cash transfers for total expenditure on temptation goods; Maluccio and Flores (2005) also present an estimate of the impact on the proportion of expenditures. For each of these studies, we examine whether the studies had sufficient statistical power to identify significant impacts on overall consumption using the same

> 7 This issue has been studied more extensively for sexual behavior in developing countries, and the evidence has been inconsistent: In Malawi and Kenya, for example, young women were more likely to report ever having had sex in a face-to-face interview, whereas they were likely to report more total partners in an audio computerassisted self-interview (Mensch, et al. 2008). In Zimbabwe, respondents also reported fewer partners in face-toface interviews (Gregson, et al. 2002). A study in Tanzania found female adolescents were more honest about sexual infection in face-to-face interviews, whereas males were less honest (Plummer, et al. 2004). A fuller list of relevant references is available in Handa et al. (2014).

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