Sex Differences in Mathematics and Reading Across Italy: The Role of Socioeconomic Factors

This meta-analysis examined over 26 million observations from Italy’s INVALSI surveys, conducted between 2009 and 2023, including students in second, fifth, eighth, tenth, and thirteenth grade across the entire Italian territory. Preliminary analyses revealed consistent patterns: boys outperformed girls in mathematics, d = .25, while girls outperformed boys in reading, d = -.29. Regarding mathematics, the geographical gradient was strongly correlated with average performance, r = -.528, with a North-South difference corresponding to approximately 2.77 IQ units. Furthermore, the sex difference in mathematics was strongly associated with the geographical gradient, r = -.817, indicating larger gaps in Northern provinces, and positively correlated with grade level, r = .386, showing that the boys’ advantage widens in higher grades. As for reading, the geographical gradient was similarly correlated with average performance r = -.603, with a North-South difference of approximately 3.44 IQ units. The sex difference in reading showed a weaker association with the geographical gradient, r = -.181, but a strong negative correlation with grade level, r = -.668, indicating that the girls’ advantage increases substantially in higher grades. Meta-regression models identified the geographical gradient, employment rate ratio, university enrollment ratio, and mean achievement score as key moderators. Specifically, for mathematics, higher women’s university enrollment was associated with smaller sex differences, whereas higher employment equality and higher overall achievement were associated with larger sex differences, favoring boys. For reading, higher women’s university enrollment and higher mean achievement were associated with larger girls’ advantages. Collectively, these results suggest that while high-performing environments tend to amplify sex differences across domains, economic productivity and specific opportunity structures can act as protective factors, offering new insights into the gender-equality paradox.