ABSTRACT
The effects of class size on student outcomes remain one of the most researched and controversial issues in the economics of education and education policy in general. In part, this reflects difficulties in credibly identifying the causal effect of class-size variation on student outcomes. This chapter surveys recent evidence that utilizes a range of approaches with the aim of providing this evidence. This research demonstrates a range from zero to substantial positive effects of class-size reductions on student attainment, where this variation in effect sizes reflects a range of factors, including empirical approaches, location, grade level, and the margins at which class-size changes occur. We additionally consider a range of recent evidence that aims to examine mechanisms behind class effects and provide tentative suggestions for future research. The aim of this chapter is to provide a starting point for researchers interested in this topic who may be daunted by the now-huge body of empirical research in the area.
