In many low income countries, teachers do not master the subject they are teaching and children learn little from attending school. Using unique cross-sectional data from nationally representative surveys from seven Sub-Saharan African countries, we propose a methodology to assess the effect of teacher knowledge on student learning. We estimate two structural parameters of a cumulative student achievement function—the contemporaneous effect of teacher content knowledge and the extent of fade out of the teachers’ impact in earlier grades—and combine them to estimate the cumulative effect of teacher knowledge on student achievement. We then calculate the learning achievements in a series of counterfactual policy experiments, showing that low teacher content knowledge can account for a substantial portion of the large learning gap we observe already after a few years of schooling and that, under plausible assumptions of the class size effects, moving students from the worst performing teachers to teacher with relatively better knowledge, will raise average student learning.

Written with Deon Filmer (World Bank), Ezequiel Molina (IIES) and Jakob Svensson (IIES)