Differences in teacher quality are commonly cited as a key determinant of the huge international student performance gaps. However, convincing evidence on this relationship is still lacking, in part because it is unclear how to measure teacher quality consistently across countries. We use unique...

Many countries, American jurisdictions and charter schools have recently embraced longer school days or more time devoted to core academic classes. Recent research generally supports the notion that additional time raises achievement, though difficulties isolating an exogenous source of...