Given the hit-or-miss quality of graduate student training, it is not surprising there are concerns about the quality of instruction TAs provide. Students have been known to shy away from courses taught by graduate students, especially when English is a second language for those instructors. Even some research has raised questions about the competence of TAs.
However, a recent study by Bettinger, Long, and Taylor (2016) sheds new light on the instruction provided by graduate students. The cohort considered by the researchers was large: a data set from 12 Ohio public four-year colleges and universities with more than 40,000 students and 2,600 graduate students. The researchers used a different statistical approach to compensate for the fact that TAs are not randomly assigned to courses and students do not randomly select courses.
And what was the surprising result? The authors explain: “We find that undergraduates who take their first course in a given subject from a graduate student are nearly twice as likely to subsequently major in that subject compared to their peers who take the same course with a full-time faculty member” (p. 75). Those differences in choice of major were not statistically significant if the course were taken during a student’s first term in college, and there were also no significant differences in the subsequent course-taking decisions or credits earned in the subject related to who taught the course. Nonetheless, taken together these findings suggest that no harm comes to students with TA teachers, and there may be some benefit.
Moreover, a benefit accrues to the TAs a well: “We find that graduate students who teach more frequently are more likely to graduate in a timely manner and more likely to be employed by a college or university in their early careers” (p. 75). Those results should not be assumed to be uniquely causal. There may be other factors at play. Perhaps only the best graduate students are chosen to teach. But even the selection factor generates a benefit in that case for students.
The authors do not explore the implications of their findings, but the results raise all sorts of interesting questions, most of them regarding full-time faculty who teach these first courses in the field and why they aren’t influencing major decisions to the same (or higher) degree than these very beginning teachers.
References
Bettinger, E. P., Long, B. T., and Taylor, E. S. (2016). When inputs are outputs: The case of graduate student instructors. Economics of Education Review, 52, 63–76.
