Help or Hinder? Adjunct Professors and Student Outcomes

College and universities are increasingly using part-time, adjunct instructors on their faculties to facilitate greater fiscal flexibility. However, critics argue that the use of adjuncts is causing the quality of higher education to deteriorate. This paper addresses questions about the impact of adjuncts on student outcomes. Using a unique dataset of public four-year colleges in Ohio, we quantify how having adjunct instructors affects student persistence after the first year. Because students taking courses from adjuncts differ systematically from other students, we use an instrumental variable strategy to address concerns about biases. The findings suggest that, in general, students taking an "adjunct-heavy" course schedule in their first semester are adversely affected. They are less likely to persist into their second year. We reconcile these findings with previous research that shows that adjuncts may encourage greater student interest in terms of major choice and subsequent enrollments in some disciplines, most notably fields tied closely to specific professions. The authors are grateful for helpful suggestions from Ronald Ehrenberg and seminar participants at the NBER Labor Studies Meetings. The authors also thank the Ohio Board of Regents for their support during this research project. Rod Chu, Darrell Glenn, Robert Sheehan, and Andy Lechler provided invaluable access and help with the data. Amanda Starc, James Carlson, Erin Riley, and Suzan Akin provided excellent research assistance. All opinions and mistakes are our own. The authors worked equally on the project and are listed alphabetically.