The Difference-in-Difference method.

This study investigates whether publicly funded summer school programs in secondary education are of substantive meaning for the math performance of students from lower socioeconomic backgrounds. More specifically, we explore whether this is the case when the summer programs are not explicitly aimed at low-SES students. In this context, we investigate whether summer schools in the Netherlands can decrease inequalities of opportunities in education. We use administrative data from Dutch secondary schools. To analyse the effect of the intervention we apply a Difference-in-Difference analysis in combination with matching estimation techniques. The results indicate that there is an overall modest effect of participation in a summer school. When analysing the SES groups separately, we observe a positive effect of participation for all three SES groups. However, the effect seems less strong for participants in the lowest and middle SES group compared to the highest SES group.