Class size effects on reading achievement in Europe: Evidence from PIRLS

Some researchers have suggested that reducing class size may result in increases in student achievement. However, the empirical evidence about class-size effects from experimental or quasi-experimental studies has been mixed overall. This study sheds more light on whether class size reduction impacts reading achievement in eight European countries: Bulgaria, Germany, Hungary, Italy, Lithuania, Romania, Slovakia, and Slovenia. We examine class size effects on reading achievement using national probability samples of fourth graders. All eight European countries had participated in the Progress in International Reading Literacy Study (PIRLS) in 2001, 2006 and 2011. Overall, the results indicate that class size effects on reading achievement are not significant across countries and years. One exception was Romania where class size effects in 2001 and 2011 were significant and negative suggesting that reducing class size corresponded to increases in reading achievement. Trends in class size effects over time were not observed.