Although primary school enrollment in developing countries has rapidly increased since 1990, the quality of education has stagnated over the years. In teaching and learning practices, textbooks are an important intermediate that links curriculum, teachers, and students. Through a randomized controlled trial in El Salvador, this study evaluated the impact of a package of interventions including the distribution of textbooks that were carefully designed to improve math learning. This study targeted primary second grade students and tracked them for two years. To capture their progress in learning over the period, this study linked math test scores at the end of the second grade and third grade, using the item response theory (IRT). The average one-year impact of the package is estimated at 0.49 standard deviations of the IRT scores. Schools in the control group began to receive the package in the second year of research. After two years of exposure to the package—as compared to students in the control group who only received one year of exposure—the impact is estimated at 0.13 standard deviations. Students in the treatment group advanced math learning in the second year of research based on the improved understanding in the previous year.
This paper was accepted in July, 2022.