Does schooling increase or reduce inequality in achievement and conscientiousness in Denmark?

What the paper says

A growing body of research has established that schooling either reduces, socioeconomic inequality in achievement or contributes equally to student, achievement. However, much of this work focuses on the early years of education and, primarily examines achievement outcomes, with little known about the effects in later, years of school, and other outcomes. This study employs a Differential Exposure, Approach, which exploits (conditionally) random variation in test dates, to assess the, impact of schooling on both students’ reading achievement and conscientiousness.The analysis draws on data from a biennial mandatory reading test administered across all Danish public schools (grades 2–8), as well as a self-reported measure of conscientiousness from an annual mandatory school survey (grades 0–8) linked with the Danish administrative register data. Results indicate that schooling reduces students’ self-reported conscientiousness, whether this reduction reflects true changes to students’ underlying personality or merely reflect temporary school fatigue is unclear. The negative effects were similar across SES. The results show that school exposure enhances reading achievement across all grades, though the marginal returns from an additional month of schooling diminish as students grow older. Schooling reduces the achievement gap in second grade among students within the same schools; however, this effect does not persist in later grades. Schooling reduces the SES gap in achievement in the early grades of schooling. In later grades, schooling affects student achievement similarly across SES status. Schooling appears to reduce self-reported conscientiousness. The decrease may reflect temporary school fatigue rather than permanent changes to conscientiousness. Schooling does not increase SES differences in students’ conscientiousness.