[Excerpt] The last two decades of the twentieth century saw a significant growth in the shares of faculty members in American colleges and universities that are part-time or are full-time without tenure-track status. Growing student enrollments faced by academic institutions during tight financial times and growing differentials between the salaries of part-time and full-time non-tenure track faculty on the one hand, and tenured and tenure-track faculty on the other hand are among the explanations given for these trends. However, there have been few econometric studies that seek to test these hypotheses.
Our paper begins by presenting information, broken down by form of control (public/private) and 1994 Carnegie Category, on how the proportions of full-time faculty at 4-year American colleges and universities that are tenured and on tenure tracks and that are not on tenure tracks have changed since 1989, using information for a consistent sample of institutions from the annual IPEDS Faculty Salary Surveysand the biennial IPEDS Fall Staff Surveys. The latter source also permits us to present similar estimates of the proportions of faculty that are employed part-time and the share of new full-time faculty appointments that are not on tenure tracks.
To analyze the role that economic variables play in causing changes in faculty employment across categories, we conduct two types of econometric analyses. First, in section III, we use panel data to estimate demand functions for tenure and tenure-track faculty on the one hand and full-time non tenure-track faculty on the other hand to learn how changes in revenues per student and the average salaries of different types of full-time faculty influence the distribution of faculty across categories of full-time faculty. We do this using both equilibrium models that assume instantaneous adjustments to changes in revenues and faculty salaries and lagged adjustment models that permit partial adjustments to equilibrium each year.
Second, in section IV, we estimate models that seek to explain the flow of new hires of each type of faculty member (rather than the levels of faculty employment) using data on new hires that are available from the IPEDS Fall Staff Surveys. To explain new hires, in addition to information on changes in revenues per student, changes in enrollment, and the levels of faculty salaries, we require information on the number of vacant positions that are available to be potentially filled. We construct information on the latter using data on the number of continuing full-time faculty members at an institution each year that the American Association of University Professors (AAUP) collects (but does not publish) as part of its annual salary survey.
Continuing faculty members in a rank are defined as the number of faculty members in a rank one year, who also are on the payroll of the institution in the next year, regardless of their rank in the second year. Summing up an institution’s continuing faculty members across ranks in a year and subtracting that number from the institution’s total faculty employment in the previous year provides us with an estimate of the number of full-time faculty vacancies that an institution could have filled in a year if it had replaced each of its departing full-time faculty members.
A brief concluding section summarizes our findings and discusses their implications for American colleges and universities and their students.