How to Improve Education Outcomes Most Efficiently ? A Comparison of 150 Interventions Using theNew Learning-Adjusted Years of Schooling Metric

Many low- and middle-income countries lag far behind high-income countries in educational accessand student learning. Limited resources mean that policymakers must make tough choices about which investmentsto make to improve education. Although hundreds of education interventions have been rigorously evaluated, makingcomparisons between the results is challenging. Some studies report changes in years of schooling; others report changesin learning. Standard deviations, the metric typically used to report learning gains, measure gains relative to a localdistribution of test scores. This metric makes it hard to judge if the gain is worth the cost in absolute terms. Thispaper proposes using learning-adjusted years of schooling (LAYS) -- which combines access and quality and comparesgains to an absolute, cross-country standard -- as a new metric for reporting gains from education interventions. Thepaper applies LAYS to compare the effectiveness (and cost-effectiveness, where cost is available) ofinterventions from 150 impact evaluations across 46 countries. The results show that some of the mostcost-effective programs deliver the equivalent of three additional years of high-quality schooling (that is,schooling at quality comparable to the highest-performing education systems) for just $100 per child -- compared withzero years for other classes of interventions.