My dissertation examines the role of horizontal stratification (qualitative differences within the same education level) in higher education for social stratification and inequality. Sociological studies, that have long debated the role of educational expansion for social mobility, have often assumed that increased access to higher education occurs uniformly. However, the limited focus on the quantitative increase in the number of highly educated individuals may obscure another important mechanism, that is, the growth of institutional heterogeneity through the proliferation of lower-tier institutions. This study examines the case of status attainment, and two critically related outcomes – assortative mating and gender stratification.

Chapter 1

Title: Horizontal Educational Stratification through a Genetic Lens: Effects of Social Background and Genetic Endowment on College Selectivity and Wages (in preparation for submission)

In this chapter, I examine the role of horizontal stratification for social mobility with a genetic lens. Specifically, I take advantage of molecular-level genetic data, that help to measure at least part of the ability endowment, to provide insights into how such biological endowments from parents are associated with social origins, access to selective colleges, and how these interactively contribute to the labor market outcomes.

Chapter 2

Title: Explaining Declining Trends in Educational Homogamy: The Role of Institutional Changes in Higher Education in Japan (in-press at Demography)

In this chapter, I examine the role of horizontal stratification for explaining educational assortative mating trends. Specifically, I examine whether the bifurcation between high- and low-tier institutions in the context of high participation in tertiary education may help us understand the mixed evidence on educational homogamy trends across countries.

Chapter 3

Title: The Role of Anticipated Futures in Gendered Educational Trajectories: Adolescents’ Expectations and Uncertainty in Japanese Selective High Schools (work in progress)

In Japan, despite women’s improved access to higher education, still only one in five applicants to the nation’s top university are women, which is extremely lower than the female share in selective institutions in other wealthier countries. In this chapter, I focus on the role of high school students’ “anticipated futures” under highly uncertain admission contexts, to provide explanations for the underrepresentation of women in Japanese selective universities.