A not-uncommon complaint of tenure-track faculty, particularly during the tenure decision year, is that some of those who are deciding their Fate would not get tenure under today's rather rigorous system of evaluation. How can the process be fair if people unqualified for tenure today participate in decisions about the tenure of others?
It's a complicated question because, although the tenure bar has definitely been raised with time, you can't know whether someone who had too-low-for-tenure-today productivity way back when would rise to the challenge of today's standards or not.
I am working very hard here to be fair and balanced about this topic. I certainly have done my share of grumbling about certain senior professors who seem to have succeeded for mysterious reasons. These particular senior professors have published only a few no/low citation papers, got few or no grants, and mostly got by on their charms, which in some cases are not considerable. How did they even get tenure back then? These extreme cases are, however, the exception, and becoming more rare with time.
I am cynical enough to think that some tenured professors can't be trusted to make a fair evaluation of their more junior colleagues, whether because they have no idea what it is like to be constantly working on manuscripts and proposals or for their own nefarious reasons. In some departments, there seem to be a few professors who reflexively vote no in tenure cases; perhaps not so much in an aggressive effort to deny the candidates tenure as to make a point that no one is good enough to deserve an easy tenure process (even if they themselves had this luxury when they got tenure in the Jurassic).
This is probably related to the phenomenon in which some spectacularly unproductive professors are particularly aggressive about questioning the superior records of younger scholars (faculty, researchers, applicants for faculty positions). These people clearly have Issues.
In my limited experience, however, these unpleasant individuals have been vastly outnumbered by more reasonable people. Perhaps I have been fortunate, but this conclusion is consistent with what I have seen during my interactions with the tenure process in many other science and engineering departments, at my own university and beyond.
In most cases, I think the system itself has enough checks and balances to keep these unfair naysayers in the minority. I am not saying that the system is completely fair; every year, deserving candidates are denied tenure and others with similar records attain it. But I do think that the process of frequent evaluation at 1-3 year intervals, although stressful, provides a lot of data and accountability to somewhat demystify the process.
It's not possible to deny a vote to all those tenured professors whose scholarly records fall below the current standards for tenure, but it is possible and necessary for everyone voting on someone else's career fate to think very carefully about what standards are being applied, whether these standards have been clearly and fairly communicated from Day One, whether the candidate has had the time and resources to fix any issues revealed during the 1-3 year reviews, and whether the candidate has met the standards for tenure according to the norms of the discipline, the department, and the university. If these requirements are emphasized and openly discussed by the department leaders with the tenured faculty, perhaps it will be more difficult for the unjustly critical to cast a hypocritical no vote.
6 months ago