The role of school socioeconomic status in early mathematical development in Chile

This preregistered study examined how school socioeconomic status (SES) relates to the development of mathematical skills. At the study's start, Chilean children were enrolled in kindergarten (n = 101; M_age = 5.9 years; 51 low SES; 48 boys), Grade 1 (n = 95; M_age = 6.8 years; 46 low SES; 52 boys), Grade 2 (n = 87; M_age = 7.9 years; 52 low SES; 47 boys), or Grade 3 (n = 84; M_age = 8.8 years; 52 low SES; 38 boys). Children completed cognitive (receptive vocabulary, number comparison, number ordering), mathematics (calculation, math fluency, applied problems), and literacy (letter-word identification, passage comprehension) tasks. Across domains, children from high-SES schools outperformed children from low-SES schools. Patterns consistent with widening SES differences were observed for mathematics outcomes that rely more heavily on formal instruction, including calculation, math fluency, and applied problems, though the timing and magnitude of these effects varied by outcome and grade. For cognitive precursors, SES differences were generally stable across grades, with the exception of receptive vocabulary, for which SES differences widened by Grade 3. Longitudinally, school SES predicted one-year gains in calculation and math fluency, but not literacy outcomes, after accounting for maternal education and cognitive precursors. These findings highlight the compounding role of school SES in children's mathematical development within a segregated education system, pointing to a need for policies and practices that promote equitable learning opportunities.