His research focuses on issues of student success and stratification of opportunity in higher education. Thomas’ earlier work in this area has centered on understanding variance in economic outcomes and indebtedness related to college and field choice. His current work is focused on defining and understanding the impacts and costs of academic pathways to and through the undergraduate years. This work incorporates the effects of students’ high school experiences, their transitions to college, and coursetaking patterns within and across postsecondary institutions. A central feature of this work involves the financial costing of these pathways and their impact on degree attainment. This work builds on his earlier research, which focused on within-school processes that sort students into widely varying college opportunity sets. Relevant published work in this area can be found in journals such as Sociology of Education, Research in Higher Education, the Review of Higher Education, and various chapters in the highly regarded Higher Education: Handbook of Theory and Research.