_Research design._ Starting with the research design of the underlying primary studies, we find that RCTs report— _ceteris paribus_ —slightly smaller effect sizes than non-RCTs, which is in line with earlier presumptions (see table 1, panel B). However, now this difference is statistically significant (see column 1 of table 3). As expected, the operationalization of treatment effects as TOT-estimates leads to inflated effect size estimates. Apparently, the delay between intervention and measurement of outcomes does not seem to be systematically related to effect sizes in this estimation (cf. supplemental appendix S3 for an alternative approach and investigation of heterogeneous treatment effects depending on delay in measurement). In addition, estimates with large inverse standard errors are associated with smaller effect sizes, indicating that larger and more precise studies report smaller effect sizes overall. However, this coefficient is small in size and insignificant.

_Intensity._ Turning to the relationship between intensity per week and duration, column 1 of table 3 shows that intensity has a significant positive effect on treatment effects on financial behavior. Thus, an increase of one hour of financial education per week leads to a 0.004 standard deviation unit increase in the impact on financial behaviors studied. Considering that the average weekly duration is in this subsample is roughly nine weeks and weekly intensity is only about four hours, doubling the weekly intensity to eight hours while keeping everything else constant at the mean, would lead to an average treatment effect around 14 percent higher than the empirical mean predicted treatment effect in this fully specified model.

_Target group._ Among participant characteristics, age and gender are not significant explanatory variables. However, the coefficient on “low income clients” is highly significant and negative, indicating that these individuals are more difficult to educate. Regarding increasing mean years of schooling at the country level, returns to additional financial education appear to diminish. This is in line with results from two studies in very different contexts (Europe and India) that report higher treatment effects for lower-educated individuals and diminishing returns to financial education upon higher baseline levels of education (cf. Cole et al. 2011; Fort et al. 2016). Similarly, the coefficient for baseline financial literacy in the population is also negative, albeit statistically insignificant. While these results suggest declining marginal returns to financial education, the negative effect for low- and lower-middle income economies—and also the above-mentioned coefficient on low-income clients— shows a countervailing influence from challenging groups or country circumstances.

_Characteristics of education._ Regarding the channel variables, column 1 shows that no alternative channel appears to be generally more or less effective than financial education in classroom settings or informational nudges (omitted category). The same is true for the setting of the intervention where school and workplace settings are not systematically different from other settings. However, mandatory financial education and implementing financial education at a “teachable moment” appear to be important. Specifically, we find, that making financial education mandatory decreases effect sizes 18