<p>There’s nothing wrong with adjuncts as such, especially if they’re used to supplement a strong roster of full-time faculty. But if they’re used as a substitute for full-time faculty, it can become a problem. There tends to be more turnover among adjuncts, for one thing, which means less faculty continuity and less institutional memory. And since generally it’s only full-time faculty (and often only tenured or tenure-track faculty) that get called on to serve on committees, take on major administrative assignments, supervise dissertations, run research labs, and so on, a low number of full-time faculty will mean those full-time faculty who remain will be spread thin and have less time to teach and interact with undergraduates.</p>
<p>You need to be careful about going just by percentages, however. I was surprised to see that my alma mater, the University of Michigan, has a relatively low percentage of full-time tenured and tenure track faculty compared to other top public research universities (44.4% tenured/tenure-track in non-medical fields, compared to 63.4% at UC Berkeley, 64.7% at UCLA, 66.4% at UNC-Chapel Hill, 61.8% at Wisconsin—but only 45.3% at UVA, similar territory to Michigan). But that percentage figure is highly misleading. Michigan actually ranks at the very top of this group of universities in absolute numbers of tenured/tenure-track faculty (1,844 at Michigan v. 1,667 at Wiscsonsin, 1,373 at UC Berkeley, and 1,447 at UCLA, all roughly comparably sized schools), as well as in its ratio of students (here counting all students, both undergrads and graduate/professional) to tenured/tenure-track faculty (22.9 students per tenured/tenure track faculty at Michigan v. 25.5 at Wisconsin, 26.2 at UC Berkeley, 27.5 at UCLA, and 25.7 at UVA; only UNC-CH clocked in slightly better, at 22.2). The reason Michigan’s percentage of tenured/tenure-track faculty is so low is that it has an exceptionally large number of non-tenured fulltime faculty (1,506 at Michigan v. 485 at Wisconsin, 235 at UC Berkeley, and 297 at UCLA). But viewed in context, it’s apparent that these non-tenured fulltime faculty represent additional faculty resources, supplementing a very strong core of tenured/tenure-track faculty that compares favorably with any institution in its peer group. As a result, Michigan’s ratio of students to fulltime faculty (including here both tenured/tenure track as well as non-tenured) is roughly half that of some schools in its peer group (12.8 students for every full-time faculty member at Michigan v. 22.5 at UC Berkeley and 23.9 at UCLA). To my mind, that’s a big positive, not a negative; it means Michigan has supplemented its core tenured/tenure track faculty, not gutted it.</p>
<p>The schools where these figures might worry me a bit are places like NYU (43,911 total students but only 1,378 tenured/tenure-track faculty, or 31.9 students per tenured/tenure-track faculty), USC (38,010 students but only 1099 tenured/tenure track faculty, or 34.6 students per tenured/tenure-track faculty), and Johns Hopkins (21,139 students but only 667 tenured/tenure-track faculty, or 31.7 students per tenured/tenure-track faculty).</p>