Instruction Time, Classroom Quality, and Academic Achievement

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 variation raise questions about the strength of much of the evidence. Moreover, it seems likely that the magnitude of any causal link between achievement and instruction time depends upon the quality of instruction, the classroom environment, and the rate at which students translate classroom time into added knowledge. In this paper we use panel data methods to investigate the pattern of instruction time effects in the 2009 Programme for International Student Assessment (PISA) data. The empirical analysis shows that achievement increases with instruction time and that the increase varies by both amount of time and classroom environment. These results indicate that school circumstances are important determinants of the likely benefits and desirability of increased instruction time.