Over-Tenured Universities: The Mathematics of Reduction
用简单数学比较了三种降低大学终身教职比例的策略：降低终身教职授予率、增加已有终身教职流失、延长试用期，发现后两者同样有效且副作用更小，对面临生源下降的大学管理者有参考价值。
Most universities anticipate an era of retrenchment over the next decade or two. The heady period of expansion fueled by the baby boom and by the jump in the percentage of high school graduates enrolling in college is now yielding to the lean years of the baby bust. As college enrollments fall, universities face a seller's market in attracting new students; on the other hand, as job openings decline, universities enjoy a buyer's market in hiring new faculty. It is thus understandable that university administrators are striving to maximize their flexibility in determining the composition of their professorial work force—to respond to shifts in student interest, to trim dead wood, and to seize opportunities to hire transcendent new Ph.D.'s. The employment guarantees of tenure make it harder to achieve this flexibility. Most universities, however, are entering the era of retrenchment with more than three-quarters of the faculty holding tenure. Consequently, many university administrators are pondering ways to reduce the tenure ratio. Attention has been focused on making tenure harder to get, i.e., on reducing the proportion of junior faculty who, after the usual trial period of five or six years, are granted tenure. This article compares this strategy with two alternatives—increasing the attrition of less-worthy tenured faculty and lengthening the average time to tenure. It turns out that in most cases even a relatively modest decrease in the tenure ratio, say from 80% to 67%, would require a radical reduction in the percentage of new faculty who can be expected to be granted tenure—e.g., from 50% to 25%. Remarkably enough, the same impact on the tenure ratio of such of halving of the chances of tenure can be achieved either by doubling average time to tenure or by doubling the attrition of already tenured faculty. Since faculty have to leave the university if denied tenure, a drastic cut in the chances of tenure may severely diminish the loyalty and the dedication to teaching of junior faculty as well as making faculty recruitment more difficult. Therefore, universities should seriously weigh alternative strategies. A variety of means exist for encouraging attrition, including holding salaries down, giving bonuses for early retirement, and making promotion from associate to full professor more selective. Lengthening the time to tenure should also be considered: many junior faculty would prefer to face a 50% chance of tenure after ten years rather than a 25% chance after five years; furthermore, the ten-year trial period would enable better evaluation of performance, as well as requiring only half as much recruiting of new junior faculty each year. The desirability of the alternative strategies depends on the specific attributes and preferences of particular universities. No panacea emerges—and it is by no means clear that a university, given the drawbacks, would be wise to attempt to reduce its tenure ratio. The simple mathematics developed in this article, however, does demonstrate that reducing the chances of tenure is certainly not the only feasible way, and in many cases probably not the best way, of reducing the tenure ratio.