Research

How do schools affect socioeconomic inequality in academic achievement? Many studies have sought to characterize the role of education in the stratification system, but few have jointly studied multiple mechanisms by which schools contribute to inequalities. This article proposes a unified theoretical framework that integrates three potentially equalizing or stratifying mechanisms of an educational system: (1) unequal access to high-quality schools; (2) heterogeneous returns to attending high-quality schools; and (3) differential selection into high-quality schools by students' socioeconomic origin (SES). Analyzing data from the Taiwan Education Panel Survey with a novel causal decomposition method, we find that 12% of the SES achievement gap at the end of high school can be explained by unequal access to high-quality high schools, as higher-SES students attend high-quality schools at a higher rate due to their higher prior achievement. At the same time, attending high-quality schools is more beneficial for students with low SES, reducing the achievement gap by 10%. Differential selection into schools explains only about 1% of the gap. Although high-quality schools benefit lower-SES students more, the equalizing potential is undermined by their unequal distribution across SES backgrounds due to the admission rule that prioritizes prior achievement. Therefore, policies that redistribute admissions to high-quality schools could help narrow the SES achievement gap.

Social scientists have long been concerned with the slowing convergence of the gender wage gap in the United States since the 1990s. While prior research has proposed various explanations for the stalled convergence, the contributions of persistent gender segregation in college majors and rising between-major earning inequality remain underexplored. This article examines how trends in the gender wage gap among college-educated workers correspond to changes in the composition of majors among men and women, as well as changes in gender-specific wage returns to different majors. Using a detailed decomposition method and data from the 2003–2023 National Survey of College Graduates, I find that 59% of the observed decrease in the wage gap is related to a greater decline in the share of women earning education degrees — a historically lower-paying field. Yet, two countervailing forces hindered further convergence. First, men earned degrees in electrical engineering and computer science at a higher rate, a field with a greater wage premium. Second, declining wage returns to education degrees disproportionately undermined women's wages, given women's continued overrepresentation in the field. Together, these two forces combined offset 78% of the gender wage convergence, which can help explain the stalled progress toward gender pay equality.