Some adjuncts certainly teach better than most tenure-line faculty members, but any research into who is better overall needs to be viewed with suspicion due to two potentially big sources of confusion. The first source of confusion is caused by the way adjuncting has shifted from a part-time job that is a totally legitimate, but tiny, part of most colleges' teaching rosters, to a full-time job that is a possibly illegitimate, and large, part of many colleges' teaching rosters. That is an issue for later discussion. The second source of confusion is that few people seem to understand why we might want to have researchers in teaching roles. This is the confusion I want to talk about, though it is too big to tackle in a single post, so I will only talk about it in the context of the recent article.
The study under question runs headlong into the latter confusion because: If there was justification for having active researchers in the classroom, it would be exactly because their classes were different in some way from those taught by non-researchers. There is also good reason to believe such courses would be different in exactly the ways that would make it difficult to compare learning between classes.
To phrase this another way: If your best options for courses at a research university are courses taught by non-research faculty, something has gone seriously wrong.
To start by giving the authors credit, the study in question was very smartly done, and does deserve to be wrestled with very seriously. Their method of assessing student learning, in particular, was quite clever. To compare quality of the instructor-types, the authors looked at eight years worth of freshmen classes at Northwestern. They started with the first semester students, taking whatever courses they ended up taking, and then measured the proportion of students likely to enroll in a second course in the same field and how well the student did in that second course. This is a great method, and counters many of the knee jerk criticisms one might level against the study. In particular, it does not rely on the grades given by the first set of instructors. They also allowed each student to act as their own control, which is very cool --- for each student they picked two subjects, one subject with a first-course taught by a tenure-track instructor, the other with a first-course taught by an non-tenure-track instructor. Then they saw if each student took a second course in either subject, and measured how well the students did.
There are two or three really important results in the study, depending on how you want to break things up. First, students are more likely to take a second course in a subject if their first course was taught by a non-tenure track faculty member. Second, students are likely to do better in their second course if their first course was taught by a non-tenure track faculty member. Third, both of the prior effects are larger for students who entered college less prepared. As the authors put it:
non-tenure track faculty appear to induce relatively marginal students, who might have been expected to perform worse in subsequent classes, to take those classes nonetheless. (p. 8)And rather than putting the expected-to-perform-worse student at risk, a first class with a non-tenure track faculty
increases the grade earned in that subsequent class (p. 9)Across all students, the increased rate of taking a second class is 7.3% or 9.3%, depending on how you count it, and the grade-increase is around a tenth of a grade point (i.e., not much, but significant nonetheless). The interaction with student's pre-college indicators is a bit more complicated, and I won't get into all the details. The interaction worth noting is that students with worse indicators had the most benefit from non-tenure track faculty (in a subsequent course) in academic subjects that administered the toughest grades.
The most easy story to draw from the data is this: Faculty who have a clear primary obligation to teach do so better. They not only inspire their students to pursue further classes in their area, they better prepare students for that future study. In particular, non-tenure line faculty take the time needed to inspire the weakest students and to give them the tools they need to succeed.
However, the most easy story is not always the correct one. I know many great adjuncts who would fit the above story perfectly. But I have a nagging feeling related to the source of confusion I highlighted above: What if the benefit of having a tenured researcher in the classroom is the type of benefit that would not show up in this comparison?
In my experience most professors, no matter their rank, are under pressure to teach their classes in a very standardized, concrete, falsely definitive way. And on that playing field, I would expect non-tenure line faculty to have an advantage. Standardized, concrete, falsely definitive classes make the students happier, and in particular makes things easier for the weaker students. Imagine, for a moment, an Intro Organic Chemistry class that threw in primary research, focused on dynamic thinking instead of memorization, and exposed students to the neigh-infinite number of factors that can effect a reaction. Compare that to an Organic Chemistry class that stuck to a highly-focused standardized textbook, tested students only on well-determined syntheses that work in the most predictable ways, and that thereby glossed over much of the complexity. Surely the latter class will result in happier students and therefore in more students taking a second chemistry course. That should be intuitive to almost anyone. However, I'd like to make the (perhaps) more controversial assertion that students in the standardized course are also more likely to do well in their next course. This is because they will likely arrive in their next course with a firmer grounding in a wide range of somewhat agreed upon materials. They will arrive in their next course more prepared for exactly that next course, but less prepared for eventually doing organic chemistry. The best students will have academic skills better able to make up for this temporary deficit, so the difference will be most visible in the weaker students.
To go back to psychology: If I had my druthers teaching Intro Psychology, it would bear little resemblance to the standard course. The course would primarily teach students to think about psychological phenomenon in a fundamentally new way (i.e., as a professional psychologist, in the ecological vein), and would not be a grab-bag of loosely strung together topics. Students who do well in this course will have begun to master this new way of thinking. However, they will not have learned as much of the litany of vocabulary and common lore that make up the majority of today's Intro Psych classes. If the mid-level class psychology these students take next is taught in a more standardized way, then those coming out of my course would likely struggle a bit more. The difference in future performance would likely be biggest for "weaker" students, i.e., those less comfortable with abstraction, critical thinking, and self-motivated assignments. They will have learned less in my class than the "stronger" students, and will have less chance to make up for that deficit with a penchant for blunt memorization of falsely-definitive factoids.
While I fully admit this initial disadvantage my students might suffer in their next class, in exchange they get a much deeper understanding of the field as a whole, and, more importantly, they get a class that couldn't have been taught to them by someone else. In other words, students in my class would get the benefit of being taught by a professional researcher, someone actively working towards rethinking the field, while students in the standardized class would get little more than what they could by reading and studying a textbook available to them for a small fee.
Of course I prefaced this by saying "If I had my druthers." The point of tenure is to allow people the security to teach such novel classes, and the point of tenuring research-active faculty (in the broad sense) is so that the faculty have the ability to teach such novel classes. Non-tenured faculty at most institutions would be foolish resist the pressures to teach standardized classes. Non-tenured faculty are much more vulnerable to the whims of unhappy students and are much more obligated to teach in a way that meets narrow expectations of other department members and administrators. Further, faculty that do not engage in research (broadly construed) are not in a position to give students a new and unique view of subject matter. While they may introduce novel pedagogical methods, by definition they are presenting materials that students could get elsewhere.
In sum, while I praise the Figlio, Schapiro, and Soter for their study, and their clever methods, I urge caution. I think that there is a value in something that research-active tenured faculty could and should offer, when teach courses, that non-research-active non-tenure-line faculty are not in a good position to offer. This is exactly the type of customized, unique-to-a-location education that should make college worthwhile, as opposed to the much cheaper option of staying home and reading books by yourself.
P.S. Introductory courses were used in the above examples because they are what the freshman students in the study were likely to take. The difference between a research-active faculty and a non-research-active faculty teaching upper level course should be even more dramatic. (And again, we will delay for later discussion the problematic fact than an increasing number of non-tenure-track faculty are research active.)
Figlio, D. N., Schapiro, M. O., & Soter, K. B. (2013). Are tenure track professors better teachers? NBER Working Paper, 19406. (Retrieved 9/12/13 from http://www.nber.org/papers/w19406)