A recent study conducted at Northwestern University found that students learned more from their adjunct instructors than their tenured or tenure track faculty. This study did not directly get at quality of instructors. What this study looks at is whether a student who takes an introductory class (e.g., economics) with a non-tenure track faculty and an introductory political science class with a tenure track professor in his or her first term at Northwestern is relatively more likely to take a second political science class than another economics class; and then, conditional on taking more classes in both subjects, are they more likely to perform better in the political science class than in the economics class. So the idea of choice indirectly gets at students’ perception of instructor quality and student learning.
Freshman student data collected from the registrar and office of admissions:
- SAT scores
- Student grades on subjects taken (obtained via student transcripts) = level of learning
- Instructor information
From Office of Admissions:
- Student’s initial declared major
- Northwestern’s five-point academic indicator scale (not explained how they have categorized students, but probably based on a combination of GPA in high school and SAT scores as predictors of academic success at the university – scale of 1 – 5, 1 being the highest and 5 the lowest ranking)
- Instructor information confirming tenure track/tenured versus non-tenure line status of all instructors
Researchers’ principal model:
The model estimates the relationship between the tenure track/tenured versus non-tenure track status of a student’s instructor and that student’s level of learning (i.e., grades). The model factors: class taken by a tenure-track vs. non-tenure track professor, students’ grade (on a four-point scale) in a particular subject area, students’ grade on subsequent classes in the same subject area.
For example, a comparison can be made about the relative performance in subsequent classes in subjects A and B of a student who took a class in subject A with a non-tenure track faculty member and subject B with a tenure track/tenured professor in their first term at Northwestern. The researchers then observed whether or not students took additional classes in each subject area.
An article in Inside Higher ED referenced this study and added that gains in learning were greater for students with the weakest academic preparation and these gains were found across a wide range of disciplines (http://www.insidehighered.com/news/2013/09/09/study-finds-students-learn-more-non-tenure-track-instructors#).
That seems to be the gist of this study. The probability calculation was complicated – but bottom line, the researchers found that students were more likely to take more classes in a given subject taught by non-tenure track faculty and perform better in the subsequent coursework than classes taught by tenure track/tenured faculty.
This report is available at http://www.nber.org/papers/w19406