Socioeconomic and Intersectional Differences in Mathematics Achievement Change: Psychosocial and Contextual Evidence from Chilean Students

Mathematics achievement is shaped by psychosocial, family, school, and contextual factors, yet less is known about how these influences are associated with longitudinal achievement change and socioeconomic inequalities. This study examined mathematics achievement change between Grade 4 and Grade 8 among 121,109 Chilean students, with particular attention to socioeconomic status (SES), sex, and Indigenous background. Longitudinal SIMCE data linked mathematics scores from Grade 4 in 2015 and Grade 8 in 2019. Three-level linear mixed-effects models were estimated, with repeated measurements nested within students and students nested within their Grade 4 schools. Model comparison was conducted using maximum likelihood, and the final model was re-estimated using restricted maximum likelihood. Academic engagement and self-efficacy, academic self-concept, parental education, cultural capital, parental educational expectations, and classroom order and engagement were positively associated with mathematics achievement, whereas school violence, peer aggression, and perceived discrimination were negatively associated with achievement. Under the linear SES specification, the best-fitting model included a Time × Sex × Indigenous Background × SES interaction, indicating differentiated socioeconomic patterns of longitudinal change. However, a sensitivity analysis treating SES as a five-category factor did not support the omnibus four-way interaction, although robust Time × SES and Time × Sex × SES interactions remained. These findings indicate that socioeconomic differences in mathematics achievement change vary by sex, while evidence for additional moderation by Indigenous background is sensitive to the functional specification of SES.