Higher education has increasingly relied on part-time, adjunct instructors. Critics argue that adjuncts reduce educational quality because they often have less education than full-time professors. On the other hand, by specializing in teaching or being concurrently employed, adjuncts could enhance learning experiences. This paper quantifies how adjuncts affect subsequent student interest and course performance relative to full-time faculty using an instrumental variable strategy that exploits variation in the composition of a department's faculty over time. The results suggest that adjuncts often have a small, positive effect on enrollment patterns, especially in fields related to particular occupations.