An oft-repeated opinion in academic departments is that the person you don't want as department chair is the one who wants to be department chair. According to this philosophy, it is the deeply reluctant who are the more desirable candidates.
But is that true? Why shouldn't those who are willing (if able) to do the job be the ones who do the job? Why do some think it is better to have as chair someone who is reluctant to take on major administrative work?
In some departments, the chair position rotates (swivels?) among the tenured professors every few years and everyone is expected to take a turn at this job. In large departments, however, there is a selection process by which a new chair is designated from among the tenured professors (typically the full professors). It is in these cases that the significance of enthusiasm vs. reluctance is relevant.
I am skeptical that reluctance can be used as a reliable indicator of whether someone will be a good department chair.
I agree that someone who wants to assume the all-powerful position of chair in order to hoard resources for their own purposes, reward friends, enact vengeance on enemies, and schedule weekly faculty meetings at 7 AM on Mondays might be a bad choice. However, in the more normal situation in which some faculty are interested in serving as department chair and others would rather focus on research and teaching, why not choose a professor who is willing?
If someone sees being department chair as a good use of their time, and possibly even interesting, and has the necessary vision and organizational skills to do a good job, I think they would be a better choice than someone who would rather have an invasive medical procedure than spend more quality time with the Dean.
10 months ago