There is a common belief that the more the time students spend in the classroom the more they learn; a conception which has been supported by considerable empirical research. However, most of these studies are correlational, which does not provide solid support for their conclusions. In this research work we intend to go a step further in the…

This study uses a newly compiled data set of instructional time and student performance by subject across German federal states for student cohorts enrolled at the primary level in the 1990s and tested at the secondary level in the 2000s. It finds evidence for the school inputs-student achievement relationship, taking nonlinearity,…