New Study: Adjuncts’ Students More Likely to Drop Courses & Get Lower Grades

by James Peterson

Di Xu, is an assistant professor of educational policy and social context at the University of California, Irvine. Her study, “Academic Performance in Community Colleges: The Influences of Part-Time and Full-Time Instructors,” was published on September 8, 2018. Xu’s study used individual transcript data to explore how initial exposure to a particular field of study with part-time adjuncts influenced student performance in current and subsequent course performance in community colleges. Dr. XuI used two empirical strategies, a two-way fixed effects model and an instrumental variable approach. The results of the study consistently suggest that part-time and adjunct faculty in community colleges are associated with higher grades in contemporaneous courses, but have negative impacts on their students’ subsequent course performance. Here are some highlights from the study.

While the adjuncts’ students grades in subsequent courses in science and health disciplines were only slightly lower (4 percent), it’s the impact adjuncts have on their students’ further education that is a cause for concern.

• Community colleges rely heavily on adjunct professors, but new research suggests that the part-time instructors may adversely affect student performance at two-year institutions, particularly in STEM and health field courses.
• Research conducted by Di Xu, an assistant professor of educational policy at the University of California, Irvine, shows that while students having an adjunct instructor got better grades in introductory courses, they were more likely to drop subsequent courses in the field of study or get, on average, 4 persent lower grades than if they were instructed by a full-time faculty member.
• The research notes that the use of adjuncts is greatest at community colleges, which play “a critical role in addressing the national equity agenda by disproportionately serving underrepresented groups.”

In another study co-authored by Xu, she suggests the negative effect on students is stronger when extra faculty members are hired temporarily than with adjuncts who have long-term employment contracts with a college. In a related working paper, she said the differences can be largely explained by “key instructor demographic and employment characteristics, including highest degree attained, whether employed full-time in the college, and whether [they] had previous work experience in non-teaching positions.” 

While part-time faculty members who also work in business and industry bring expertise and insights to the classroom, they typically are less available to interact with students outside of class. Some experts also say that students who take more courses from adjunct faculty members are less likely to graduate or transfer, while research shows that there are positive educational outcomes from taking courses from full-time professors, including higher grades and retention.

The National Center for Education Statistics has reported that the number of full-time faculty members increased by about 7 percent in the five years ending in 2016, while part-time faculty members decreased by about 4 percent during that period after a 74 percent rise over the previous dozen years.