School segregation and its impact on the academic performance of primary school students in Spain

This article studies the effects of social inequality on the schooling of pupils in primary education students by schools and its impact on unequal educational achievement in external assessment tests. The current reality, and the past, show adverse effects on the academic performance of students from socio-economically and culturally disadvantaged backgrounds, who are more likely to be enrolled in schools segregated by social composition. The democratization of education with full primary schooling in Spain for decades has not resolved the randomness of students' outcomes that would be expected in schooling processes guided by the principle of equal opportunities. The school social composition variable, created with a socio-economic and cultural status index, shows significant effects on the mathematics outcomes of primary school students, although schools with the same social class composition show significant variability between them, ensuring that schools can change academic outcomes, regardless of their characterization by the socioeconomic backgrounds of their student body. Data comes from the TIMSS 2019 Report, published by the IEA in December 2020.