This study aims to identify the main determinants of student performance in reading and
maths across eight European Union countries (Austria, Croatia, Germany, Hungary, Italy,
Portugal, Slovakia, and Slovenia). Based on student-level data from the OECD’s PISA
2018 survey and by means of the application of efficient algorithms, we highlight that the
number of books at home and a variable combining the type and location of their school
represent the most important predictors of student performance in all of the analysed
countries, while other school characteristics are rarely relevant. Econometric results show
that students attending vocational schools perform significantly worse than those in
general schools, except in Portugal. Considering only general school students, the
differences between big and small cities are not statistically significant, while among
students in vocational schools, those in a small city tend to perform better than those in a
big city. Through the Gelbach decomposition method, which allows measuring the
relative importance of observable characteristics in explaining a gap, we show that the
differences in test scores between big and small cities depend on school characteristics,
while the differences between general and vocational schools are mainly explained by
family social statu