The proposed project is a substantive analysis utilizing the NEPS database. Using data from the Thuringia data collections of the 2010 and 2011 Abitur student cohorts, the project will examine the consequences of a major reform of upper-secondary education that took place between the two cohorts and involved, among other aspects, the abolishment of the traditional differentiation between advanced and basic courses in mathematics, German, and foreign language. We will focus on three aspects: First, what is the impact of this major school reform on achievement and other outcomes? Second, to what extent does the reform help in homogenizing achievement within and across schools? Third, does the reform affect differences among sexes in academic attainment and educational choice? The findings will be important by themselves, but will also be relevant for the interpretation of findings from a multi-cohort longitudinal study such as NEPS.