Testing cross-group comparability of INVALSI scores using moderated factor analysis

This study, using data from the 2022–2023 INVALSI assessment, examined whether differences in mathematics and reading achievement, in terms of both mean scores and variability, exist between northern and southern Italian provinces and between boys and girls in fifth grade ( M age = 10.96, SD = 0.30, range = 9–13). We used a moderated factor analysis on a representative sample of about 10,000 students to test whether the differences reflected true underlying abilities or item-specific biases. As for mathematics, results showed that girls scored slightly lower and showed less variability compared to boys, while students from southern provinces showed a negligible mean advantage. In reading, girls scored higher. Students from southern provinces scored lower, with no meaningful variability differences. The analysis also revealed differential item functioning in both mathematics and reading, suggesting item-specific biases in relation to sex and provinces. Overall, these findings suggest that the achievement gaps reflect the complex interaction between student abilities and item-specific bias across different demographic characteristics.