This paper reviews and interprets the evidence from 223 rigorous impact evaluations of educational initiatives conducted in 56 low-and middle-income countries. We consider for inclusion in our review all studies in recent syntheses, which have reached seemingly conflicting conclusions about which interventions improve educational outcomes. We group interventions based on their theory of action. We derive four lessons from the studies we review. First, reducing the costs of going to school and expanding schooling options increase attendance and attainment, but do not consistently increase student achievement. Second, providing information about school quality, developmentally appropriate parenting practices, and the economic returns to schooling affects the actions of parents and the achievement of children and adolescents. Third, more or better resources improve student achievement only if they result in changes in children's daily experiences at school. Finally, well-designed incentives increase teacher effort and student achievement from very low levels, but low-skilled teachers need specific guidance to reach minimally acceptable levels of instruction.
Interventions.We include studies of educational interventions, such as offering computer-assisted learning or altering incentives for teachers. We also include studies of health interventions, such as providing deworming drugs and iron supplements, that include at least one of the educational outcomes mentioned above.
Methods.We only include studies that take advantage of exogenous variation in the receipt of the intervention, either by randomly assigning individuals to a treatment or by exploiting quasi-random variation in treatment assignment from natural experiments. Included studies based on natural experiments use differences-in-differences, regression discontinuities, and/or instrumental variables to estimate the causal impacts of interventions. We do not consider studies that attempt to estimate counterfactual outcomes either by employing matching methods or fixed effects for individuals in pre-post comparisons.
Literature SearchWe searched for studies in English in peer-reviewed journals, working paper series, and academic conferences. We conducted the final search that we describe below from January to September 2015. Figure 1 offers an overview of the search and review process. 3 Citation tracking. We consulted eight reviews of impact evaluations of educational interventions in developing countries and tracked the citations. These included meta-analyses, narrative, and vote-counting reviews. 4 This search produced 253 studies, of which 119 met our inclusion criteria.