Does school SES matter less for high-performing students than for their lower-performing peers? A quantile regression analysis of PISA 2018 Australia.

Background: While the relationship between school socioeconomic composition and student academic outcomes is well established, knowledge about differential effects is not extensive. In particular, little is known whether the relationship differs for students with varying levels of academic performance. We examined whether the school socioeconomic composition effect on academic achievement is stronger or weaker for high-performing students than for average- and low-performing students. Australia is a theoretically interesting case study as it has high levels of school socioeconomic segregation compared to other economically developed countries. Methods: We conducted quantile regression analysis using data from the Australia PISA 2018 sample (N = 14,273 15-year-old students). We examined the effect of school socioeconomic status (school SES) on student performance in reading, mathematical and scientific literacy. Results: We found that the school socioeconomic composition effect is substantial and is similar for all students, regardless of their level of academic performance. The findings also show that school SES is a stronger predictor than student SES for all student performance quintiles, and the size of the school SES effect relative to the size of student SES effect is larger in lower performance quintiles. Conclusions: These results indicate no differential effect of school SES on reading, mathematical or scientific literacy for students of varying levels of academic performance. The relationship is similarly strong and positive for high-performing students as it is for their lower performing peers. As school SES is a strong predictor for all students regardless of their level of academic performance, we argue that equity of educational outcomes can be best achieved by policies and structures that promote socioeconomically mixed rather than segregated schools. We also call for more research that seeks to identify and understand possible differential effects of school socioeconomic composition on a range of academic and non-cognitive student outcomes.