School autonomy in content, hiring and salaries is also associated with higher student learning outcomes on average (Hanushek et al., The decomposition results show that 11% of the explained part of the achievement gap is driven by differences in the responsibility for curriculum and resources. The first term on the right hand-side corresponds to the part of the differential in educational performance attributable to observed individual, school and teacher characteristics, that is, how much students in the bottom quartile would score differently if they had the same individual and school characteristics as students in the top quartile ESCS. The second term, the return effect, shows how much low ESCS students would hypothetically be better if they experience the same production process of schooling given their own characteristics. For instance, the provision of extra-curricular activities in schools is also a driver of socio-economic gaps in achievement. Having creative extra-curricular activities in school appeals to be an important factor in Switzerland, Turkey and the United States, for instance.