Smaller classes = better performance?

What reforms should be implement in the German educational system? In this and the next three issues of ifo Schnelldienst a series of articles entitled "The Contribution of Economics to the School Debate" will report on the numerous studies of the Department of Human Capital and Structural Change of the Ifo Institute on four central educational-policy issues. With the help of empirical research methods, lessons will be drawn from international pupil performance comparisons such as PISA, IGLOO and TIMSS for school policies in Germany. This article deals with the question of the extent to which pupil performance can be improved with smaller class sizes. The microeconomic studies have come to the conclusion that a reduction of class sizes does not necessarily have a significant learning effect.