In this dissertation, I explore the construction and reproduction of social identities (race, ethnicity, sexual orientation, and gender identity) in educational policy and research. Framed through a Foucauldian genealogy of knowledge-making practices, I focus on the discourses of social identities embedded in the (re)production of data in educational research. Drawing from sociohistorical methods and bibliometrics, I examine three distinct, yet interrelated, domains. First, I explore the construction of datasets used in postsecondary research, including a federal dataset (the Integrated Postsecondary Education Data System) and a private nationally-representative survey of students (The Freshman Survey). Secondly, I consider the uses of data emerging from these databases by examining 21,069 peer-reviewed articles published in eleven journals of educational research. Lastly, I examine the discursive practices of of social identities in the context of a specific postsecondary institution (East University, a pseudonym), where I connect administrators’ perspectives on demographic data collection practices with emerging federal standards. Findings suggest that there is a need for increased critical data literacy to understand the points of convergence between the conceptual framing of race/ethnicity and sexual orientation/gender identity. I suggest a need for more coalitional politics in the production of educational research as a strategy to enhance how social identities are understood in contemporary educational research.