Freshman seminars are a ubiquitous offering in higher education, but they have not been evaluated using matched comparisons with data at scale. In this work, we use transcript data on over 76,000 students to examine the impact of first-year interest groups (FIGs) on student graduation and retention. We first apply propensity score matching on course-level data to account for selection bias. We find that graduation and re-enrollment rates for FIG students were higher than non-FIG students, an effect that was more pronounced for self-identified underrepresented racial minority students. We then employ topic modeling to analyze survey responses from over 12,500 FIG students to find that social aspects of FIGs were most beneficial to students. Interestingly, references to social aspects were not disproportionately present in the responses of self-identified underrepresented racial minority students.