An FSP reader has a conundrum.
Imagine that you find yourself in this situation (anecdote condensed and edited from the original e-mail): A friend and co-worker has lost his/her job. You think this person has been treated unfairly, but you don't know the official facts of the case. Rumor has it that this person had done unethical things, but you have worked closely with this person and had found him/her to be very professional and reliable. On the basis of your own very positive professional interactions with this person, you write positive letters of reference for faculty jobs.
You later receive credible information indicating that this person was in fact lying about a great many things to a great many people, and that there was substantial unethical conduct. You can no longer stand by the statements in the letters of reference that you sent on this person's behalf.
This person claims to have found a position that will begin in the fall, but you don't know if this is true and there is no one at that school whom you can ask informally. A web search doesn't turn up anything, but it probably wouldn't for a recent hire anyway.
Do you have an ethical obligation to contact the schools to which you sent the positive recommendations and inform them that you can no longer stand by the statements to which you signed your name? Would search committees and department chairs want to know this?
Aside from the ethical considerations, what might be the consequences of these now-discredited letters for your professional reputation, especially if you are an early career faculty member trying to get established? Are the consequences worse if you retract your statement or if you do nothing?
What would you do?
First, I want to reassure my correspondent that he/she should not regret writing the positive letters. The letters were written in good faith, based on personal experiences working with the colleague in question. The letter no doubt mentioned these positive interactions, perhaps providing specific examples. If there were no indications of unethical behavior in these interactions, the letter was a fair statement of what the letter writer knew to be true.
If the letter stayed close to the specific interactions that the letter writer had with this colleague, perhaps a retraction is not necessary. If, however, the letter writer made some broader statements that really should be retracted, perhaps a brief letter should be sent to the relevant search committee chairs and/or department chairs.
The letter need not elaborate on the situation, but could just say something like "Owing to facts that have come to my attention since I wrote the letter on behalf of Colleague X, I can no longer stand by the positive letter that I wrote on his/her behalf. Please retract my letter, if this is possible and relevant to your search." You can decide whether you are comfortable mentioning that you are willing to provide further explanation if necessary, and then list your phone number.
If Colleague X has a new job, there must have been more than one positive letter.
Another possibility is to discuss this with a trusted senior colleague -- e.g., a mentor or the department chair. Perhaps they can intercede in the situation, especially if there is a senior person with more direct knowledge of the unethical doings of Colleague X who would be willing to help figure out the best course of action.
But perhaps various readers will have various other suggestions..
6 hours ago