How big are effect sizes in international education studies?

In recent years, a growing literature has measured the impact of education interventions in low- and middle-income countries on both access and learning outcomes. But interpretation of those effect sizes as large or small tends to rely on benchmarks developed by a psychologist in the United States in the 1960s. In this paper, we demonstrate the distribution of standardized effect sizes on learning and access from hundreds of studies from low- and middle-income countries.