It’s time to learn: School institutions and returns to instruction time

•This paper investigates whether the effects of a reform that substantially increased daily instruction time in Chilean schools vary depending on school institutions.•Exploiting an IV strategy and focusing on incumbent students, we show that students attending no-fee charter schools experienced larger gains than students attending public schools.•These two types of schools, which cater to similar students but differ in their levels of autonomy, adjusted teaching hours in different ways: no-fee charter schools relied more on hiring new teachers and less on increasing incumbent teachers’ working hours. This paper investigates whether the effects of a reform that substantially increased daily instruction time in Chilean primary schools vary depending on school institutions. Focusing on incumbent students and exploiting an IV strategy, we find that longer daily schedules increase reading scores at the end of fourth grade and that the benefits are greater for pupils who began primary education in no-fee charter schools rather than in public schools. We provide evidence that these two types of publicly subsidized establishments, which cater to similar students but differ in their degree of autonomy, expand the teaching input in different ways: in order to provide the additional instruction time, no-fee charter schools rely more on hiring new teachers and less on increasing teachers’ working hours than public schools do.