Wodurch kann die soziale Ungleichheit des Schulerfolgs am stärksten verringert werden?

Social inequality of student achievement in school has a variety of causes, all of them are well investigated scientifically. But, if a particular cause could be neutralized, which of these causes would have the strongest effect of reducing social inequality? Based on data of the PISA 2000 study, the contribution argues that the secondary social effect, which mainly represents the parental decisions for transitions to different branches of the higher educational system, has at least the same quantity as the primary social effect, which consists in all family background conditions of a student. Simple simulations show how the social inequality will change, if either the primary or the secondary social effect are neutralized. These changes cannot be forecasted in an easy or linear way under different conditions.