interventions. If an intervention increases learning and the effects can be sustained in human capital accumulation, we can calculate the lifelong wage gains from that increased learning. We use the returns to cognitive skills among adults to project the effects of improved learning on lifetime earnings.<sup>4</sup> The net present value (NPV) of lifetime earnings is – on the one hand – a reductive way to think about the value of improved learning, but it has the distinct advantage of allowing concrete discussion of the potential returns to education interventions, which may facilitate discussions of education investments relative to other investments with non‐education experts, such as Ministers of Finance.

The second objective is to characterize the size of the impacts of these interventions relative to learning in a business‐as‐usual setting. The motivation for the first objective is that a common critique of the learning interventions characterized above is that the average effect is inadequate to make a substantive difference (Alkire et al. 2018). For example, the median effect of pedagogical interventions from a recent review – including experimental and quasi‐experimental studies – was 0.13 standard deviation in learning (Snilstveit et al. 2015). The median effect across randomized controlled trials in a recent systematic review (McEwan 2015) was 0.07 standard deviation. But how much do students learn in their education systems normally? Are these effects small or big next to a realistic counterfactual of education in low‐ and middle‐ income countries? This paper characterizes the size of a range of learning interventions relative to what students normally learn in school in low‐ and middle‐income countries.

Of course, knowing the returns is only one side of the equation: adding cost data would allow policy makers not only to understand the metric by which the benefits are measured, but also to make fully informed decisions. Unfortunately, cost data are reported far less systematically and less often than impact estimates. However, recent work has provided estimates across a range of studies (J‐PAL 2014). We use those estimates to demonstrate how our method – of translating learning gains into equivalent years of schooling and into increased potential earnings – could be extended to demonstrate the equivalent years of schooling (EYOS) per $100 and the benefit‐cost ratio of investment.

To convert test score gains into additional years of schooling or increased wages, we use data on the relative wages and the relative schooling of individuals with different levels of cognitive performance. A group of new, comparable international assessments measuring adult cognitive skills in low‐ and middle‐ income countries, the Skills Towards Employability and Productivity program (STEP), along with some other, stand‐alone surveys provide exactly that (Hanushek et al. 2015; Valerio, Sánchez Puerta, et al. 2016a; Díaz, Arias, and Tudela 2012; Aslam et al. 2011; Valerio, Sanchez‐Puerta, et al. 2016).<sup>5</sup> We find that across 5 STEP countries, one standard deviation gain in literacy skill is associated with between 4.7 and 6.8 additional years of schooling, depending on the estimation method. In other words, over the course of a business‐as‐usual school year, students learn between 0.15 and 0.21 standard deviation of literacy ability.<sup>6</sup> At the same time, one promising set of interventions – structured pedagogical improvements (or improving the quality of teaching with detailed guidance to instructors) – has an average effect size of 0.13 standard deviation, which means these interventions help students to learn what they would normally learn in between 0.6 and 0.9 years of business‐as‐usual schooling. Impact

> 4 Muralidharan and Sundararaman (2011) use a similar approach for a single program, to calculate the internal rate of return of a teacher performance pay program in India.

> 5 The Programme for the International Assessment of Adult Competencies (PIAAC) provides similar data for high‐ income countries.

> 6 Because this compares individuals with different completed years of schooling, it is net of the depreciation that takes place during the holidays between school years.

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