Are Tenured Professors Really Worse Teachers? A Lit Review

The answer is complicated. But research shows that by replacing them with low-paid adjuncts, colleges could be hurting students.


Earlier this month, a team of researchers at Northwestern University, including its president, Morton Schapiro, released a paper titled, "Are Tenured Professors Better Teachers?" Their answer, based on eight years of the school's student records, was essentially no. On average, tenure-line profs actually underperformed compared to their tenure-ineligible colleagues, at least when it came to the task of teaching first-term freshmen.

I'm not writing about this paper for a second time now because I particularly love my alma mater. Rather, this isolated, interesting study on a very specific university — with results that might not be generalizable beyond a handful of similar institutions — has managed to cause a great deal of controversy in academic circles, where some have interpreted it as a politically motivated attack on the entire concept of tenure.

Frankly, I deserve some of the blame for that. I slapped a broad, somewhat provocative headline on my own post about the study, then saved the careful qualifications for the story itself. But there was a much deeper cause behind the uproar. Tenure is slowly disintegrating, and that issue is very raw within higher education, more so than those outside the professoriate usually appreciate. Over the years, colleges of all stripes have chosen to save on their instruction costs by replacing full-time, tenured faculty with adjunct professors, who work on contract, often for breathtakingly low wages and no benefits. We're talking about Ph.D.'s who have to survive on food-stamps, in some exceptional but illustrative cases. Any study which might appear, even on a surface level, to validate that evolution from a teaching standpoint was sure to provoke some anxiety. As adjunct and writer Rebecca Schuman put it:

I fear that the result of this study will be trumpeted around universities with much less revenue and much lower adjunct pay than Northwestern, to justify the idea that, as Pannapacker has put it, since children make the best chimney sweeps, we should keep sticking children up chimneys.

“Since professors who work around rat infestations and hold office hours out of their cars make the ‘best’ teachers, we should kill that pesky tenure line and replace it, not with a humane multi-year, infinitely-renewable full-time contract position, but with four adjuncts whose combined wages equal that of a high-school teacher ten years their junior. And they can hold office hours from their 1996 Subarus, while what once were faculty offices get commandeered by a new fundraising office, tasked to support a new UltraDorm/strip mall with Jacuzzi tubs on every floor.” Don’t worry, they actually teach BETTER under those conditions! They like them!

So let's be clear today: Nothing about the Northwestern study suggests that colleges should embrace the rat-hole model of labor management. Rather, it's another piece of a growing economics literature that, taken as a whole, suggests exactly the opposite: Poorly paid, part-time faculty are poor substitutes for full-time professors.

What the Northwestern Study Says (and Doesn't Say)

What precisely did the Northwestern study show? In short, it found that the university's non-tenured faculty were better both at inspiring students to study a subject and at preparing them to do it. Freshmen were more likely to take an advanced course in a field, and generally earned higher grades in it, if a professor who was not tenured or on the tenure track taught their introductory class. The differences weren't enormous, but they were noticeable and consistent across different academic departments. On average, students were 7 percentage points more likely to take an advanced course in a discipline after starting off with a non-tenured prof, and earned around 0.06 to .12 grade points better in their second class (on a four point scale).

But here's the key bit, the absolutely essential context. The study did not show that adjuncts in particular make better teachers than tenured faculty. In fact, contrary to some of the headlines it generated, the study wasn't really about adjuncts at all.* Northwestern employs a large number of full-time, non-tenure track lecturers who, while they aren't necessarily compensated like star research profs, aren't subsisting on ramen and Mountain Dew wages either. Take Mark Witte, who has been teaching economics to Northwestern undergrads for about 25 years. Students consider him a campus superstar. And as USA Today noted, he doesn't have tenure. According to the Department of Education, the school's full-time lecturers like Witte make about $62,000 a year, on average (I'm guessing he makes much more, given the time he's been around and since he has the words "senior" and "distinguished" in his title).

Northwestern economist David Figlio, one of the study's co-authors, told me that at least 82 percent of the credit hours taught by non-tenured faculty were handled by lecturers like Witte.** And he noted that 99.4 percent of all non-tenure-track professors the study examined had worked with the school for at least six quarters. In other words, it was looking at experienced teachers who enjoyed longstanding relationships with the university. And if the self-reported data in the Chronicle of Higher Education's "Adjunct Project" are any indicator, Northwestern part-time profs are paid far better than your typical adjunct.

To review, what does the study tell us? If colleges pay their professors a middle-class wage to teach year-in and year-out, they might just do a better job of it than faculty who focus on research and publishing.

What the Other Studies Say

Now time for the big picture. The Northwestern study is just one paper, part of a small-but-growing volume of economics research into which kinds of professors make the best teachers. And collectively, they suggest that schools may be hurting students by over-relying on adjuncts, especially at the community college level, where part-timers are most prevalent.

In a 2005 article published in the Journal of Human Resources, Ronald Ehrenberg and Liang Zhang looked at data from almost 5,000 colleges and universities, and ultimately concluded that schools with fewer tenure-track faculty have lower graduation rates. Unfortunately, cause and effect were a bit murky. The study only looked at schools as a whole, rather than individual students, so it was difficult to tell whether they were dropping out because they were taking classes from adjuncts and lecturers, or if colleges with fewer tenured faculty were dealing with other internal problems that drove down graduation rates. Nonetheless, it suggested that a high ratio of non-tenure track professors wasn't exactly a sign of institutional health.

In 2006, however, Eric Bettinger and Bridget Terry Long published a book chapter that did address the graduation rate question by looking at student data. Analyzing the records of 43,000 undergraduates at public, four-year colleges in Ohio, they reached the "straightforward and unambiguous" result that freshman taught by adjuncts were more likely to drop out. In their words:

In the first semester of students’ academic careers, it matters what types of professors they meet on campus. If they take large proportions of classes from adjuncts and graduate students (after controlling for selection bias), they are more likely to drop out of the institution. This likely validates claims that adjuncts are ill-prepared to help integrate new students into a specific college.

Of note here: The big divide wasn't between tenured and non-tenured professors, but part-time vs. full-time.

Four years later, Bettinger and Long published a second study that added some interesting nuances to their findings. Ohio freshmen, they found, were actually more likely to take additional classes in a career-oriented field (think business, journalism, or computer science) if their first course was taught by an adjunct. In more academic departments (think English or History) students taught by adjuncts were less likely to come back for more. Once they looked beyond freshmen year, the authors found that adjuncts had a positive effect on student interest in every field, though it was still strongest in pre-professional areas of study.

They also discovered a very telling detail: older adjuncts were more effective than younger ones. The paper theorized, very reasonably, that part-time faculty with industry experience might be good at inspiring students to get more deeply involved in their areas of expertise. What they didn't say, but I think is worth noting, is that professionals who teach part-time also often command higher pay from universities compared to, say, young humanities Ph.D.'s, and are less reliant on their university paycheck for financial stability. A retired executive teaching in his spare hours probably has more time to devote to students than an adjunct juggling 3 or more courses to make ends meet.

Reflecting on both studies, the team concluded that while a faculty full of adjuncts might hurt graduation rates overall, part-timers could still be very effective in certain subjects — especially pre-professional fields. Adjuncts might be great for teaching high level computer science and less great for teaching Chaucer.

But what about those who aren't lucky enough to attend a four-year college, the community college students who tend to be at the greatest risk of failure? As you might suspect, they also benefit from being taught by full-time professors. A 2009 article by Audrey Yaeger and M. Kevin Yeagen, for instance, looked at a sample of 178,000 students at 107 different community colleges in California and found that taking more courses from adjuncts was associated with a higher chance of dropping out.

Indeed, a 10% increase in the overall proportion of credits earned in courses taught by part-time faculty members reduced the students’ likelihood of earning an associate’s degree by 1%. This effect may seem quite small; however, considering that the average student earned approximately 50% of all of his or her credit hours in courses taught by part-time faculty members, the average student became 5% less likely to graduate with an associate’s degree compared to his or her peers whose courses were taught by full-time faculty only. 

Those findings jibed with a much smaller scale, but no less intriguing, paper released this year by Matthew Chingos of Brookings. Chingos studied a single intermediate algebra class at Glendale Community College, also in California, where students taught by different instructors all took a communal final. In the end, he analyzed more than 8,000 students and 72 instructors. Students who took their class with a full-time professor, in the end, tended to score higher on the big test.

At the sorts of colleges and universities that educate most Americans, it seems full-time professors are better at helping students stay in school than adjuncts. But why? A 2007 article in the Review of Higher Education by Paul Umbach offers a few clues.

Umbach looked at more than 17,000 responses to a voluntary survey of faculty at 130 different institutions to find out if tenure-track and non-tenure track professors approached teaching in systematically different ways. And, in fact, they did. Compared to tenure-track academics, adjuncts spent less time preparing for class, were less likely to challenge their students academically (judged by factors like the number of papers or hours of homework assigned), were less likely to use active teaching techniques (think small group discussions and in-class assignments, instead of lectures), and spent less time interacting with students, both in and out of class.

It's not hard to see how some of those differences could have a major impact on undergraduate success. For instance, it's long been established that students are more likely to stay in school when they have a chance to interact with their professors, both in and out of the classroom. If adjuncts really do spend less time working with students personally, perhaps because they're skipping from college to college trying to teach enough courses to pay their rent, that might help explain why they seem to be bad for graduation rates, in some circumstances. As Umbach put it, judging from their self-reports, the adjuncts were "underperforming in their delivery of undergraduate instruction."

But that wasn't the end of the story. While the differences between tenure-track faculty and adjuncts were rather large, the differences between tenure-trackers and their full-time, tenure-ineligible colleagues were not. The pure teachers spent a bit less time interacting with students outside of class, but more time preparing for their courses. In a phone conversation, Umbach told me the gaps were essentially "negligible."

Why All this Matters

This isn't a complete rundown of all the research on this topic, nor are any of these studies definitive. Each has its own shortcomings and methodological challenges. But read together, I think they can begin to tell us a few things. Tenured professors don't necessarily make the best teachers in every subject or school. Adjuncts might be excellent for teaching certain pre-professional courses. But as a whole, students, and especially at-risk students like young freshmen and community colleges attendees, appear to be better off with a full-time professor, whether they're tenured or not.

Hopefully, though, there will be more research. Cedar Reiner, a psychology professor at Randolph Macon College, recently argued on this site that we shouldn't think of education as a labor or economic issue. But higher ed is at an economic crossroads; the labor model is changing whether we like it or not, and it's changing in ways that may limit the time and energy professors can devote to teaching, both in the classroom and out. We owe it to ourselves to find out whether that's costing students.

*Credit where it's due: While I was very explicit in my initial post that the study wasn't just about adjuncts, other bloggers and writers have drilled down much more carefully on that point. The Little Professor had some particularly useful comments to make.

**Clarification: Based on my first conversation with Figlio, an earlier version of this post reported that the paper's data didn't allow the authors to tell which non-tenure faculty were full-time, and which were adjuncts. After the story was published, he emailed to explain that, while they couldn't find a precise number, the data did let them set the lower bound of 82 percent.  He also noted that teaching fellows and grad students were excluded from the data.