aggression. For instance, we can think of some acts as having consumption value that is fleeting (the pleasure from expressing anger) or persistent (deterring future slights). In this case, _σ <_ 0. Like crime, these acts carry a risk of future punishment.

If the criminal wage is zero, there is still a tradeoff between the consumption value today and the risk of punishment tomorrow, and the main comparative statics of therapy are similar to the case of crime: instilling values against violence (increasing _σ_ ) will reduce aggression; and increasing time consistency, _β_ , also reduces aggression. Cash, however, will have little deterrent effect on aggression.<sup>26</sup>

# **4 Data**

We tried to survey each subject five times: (i) at baseline prior to the intervention; (ii and iii) at “short-run” endline surveys 2 and 5 weeks after the grants; and (iv and v) at two “longrun” endline surveys 12 and 13 months after grants.<sup>27</sup> We ran pairs of surveys to reduce noise in outcomes with potentially low autocorrelation such as earnings or criminal activity. To measure time preferences, risk aversion, and baseline cognitive abilities (such as executive function), following each survey the respondents also conducted 45 minutes of incentivized games and tests (see Appendix D for measurement details). The winnings from all survey activities equalled about a half day’s wages.

**Response rates** This sample was mobile and difficult to track. Roughly 40% changed locations between surveys, many changing sleeping places every few weeks or nights. Just 30% had mobile phones. Most went by several aliases, and may have been on the run.

To minimize attrition, we collected extensive contact information (all known addresses, plus at least five close contacts), and went to extreme effort to locate each person, wherever they had moved, averaging three to four days of searching per respondent per survey.

We collected data on 92.7% across all endline surveys. Attrition is relatively unsystematic: treatment arms had similar response rates (within 0.4% of the control group) while a test of joint significance of all baseline covariates yields _p_ = 0 _._ 328 .<sup>28</sup>

> 26In this simple case, there is no role for self control skills, _θ_ , in aggression. This is a drawback of adapting the pecuniary crime model, since STYL explicitly teaches men skills to regulate their emotions in charged, automatic situations. In some sense, then, STYL may not only change the underlying value of _σ_ (the extent of one’s desire not to engage in criminal activity) but also one’s ability to ensure that expressed actions conform to the underlying preferences rather than succumbing to immediate temptation or anger. This is functionally equivalent to predictions associated with a larger _σ_ .

> 27The exception is the 100 men in the pilot, which had a single “short run” survey 3 weeks after grants. Actual survey times were, on average, 2.2, 5.7, 55.4 and 61.1 weeks after grants. Surveys were 90 minutes long and delivered verbally by enumerators in Liberian English on handheld computers.

> 28See Appendix A.3 for tracking techniques, response rates by survey wave and treatment group, and

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