Professors are frequently asked to write letters of reference: recommendation letters for undergrads applying to grad school, graduate students and postdocs seeking postdocs or jobs; evaluation letters for tenure-track faculty who are being considered for tenure, as well as for faculty at various career stages who are being nominated for honors or awards. If I agree to write a letter for someone, I will not write a negative one. If I cannot in good conscience write one that is positive, then I will refuse to write a letter entirely. 

If someone gets a PhD degree in my group, I endorse that person and I vouch for them. Hey, PhD is thicker than water, right? It’s not without reason that a PhD advisor-advisee relationship constitutes a lifetime conflict of interest in the context of the NSF proposal review. I will write letters for students and postdocs as often and for as long as they need them, until one of us drops dead. I would never have a problem with any of my former students or postdocs seeing the letters that I have written for them.

In the context of evaluating tenure-track applications, the issue of the letters of reference comes up for candidates who have survived at least the first and often even the second cut.

For most faculty candidates, the PhD and postdoc advisors are at the top of the reference list, which indicates that the candidate considers them someone on whose enthusiastic support he or she counts. In the vast majority of cases, this trust is warranted: the PhD and postdoc advisors usually promptly respond to the requests for letters and send recommendations that are detailed, informative, and usually glowing. This expediency holds even for the busiest and most famous among former advisors, which goes to show that if something is important to a person, they will find the time to do it.

But then there are others…

For instance, I know a successful mid-career colleague who did not put the PhD advisor on the list of references at all back when he was first applying for tenure-track jobs. I don’t even think the two of them got along that poorly, I mean the colleague published a lot and well as a grad student, but I can imagine he might have been a handful on account of having a very strong personality. I really don’t think the advisor would have written a bad letter, but I suppose you never know. The colleague had decided he had stronger and more enthusiastic references elsewhere and, while he knows this conspicuous absence of the PhD advisor’s letter raised red flags with some hiring committees, he was ultimately able to land a good tenure-track position and is now very successful.

Then there is my favorite from a few years back, where the PhD advisor wrote a paragraph-long email basically saying the candidate was good and productive. Nothing bad, but a freakin’ paragraph. It raised all sorts of questions about the candidate and I think ultimately contributed to them not getting an offer.

I have seen cases where the PhD advisor or the postdoc advisor is near the bottom of  a lengthy list of references. Usually, from the CV, you can see a clear correlation  with the person not having published very well during the PhD/postdoc. In a few cases, the advisor had a reputation as being very difficult to work with. Unfortunately, all this does cast a shadow of doubt on the applicant, but it does also reveal that the applicant knew what was going on, knew that this advisor was not to be counted on. In my experience from the search committees, I am going to say that having a so-so relationship with the PhD advisor can be remedied by great postdoc experiences. I have, unfortunately, seen candidates with a great PhD but a ho-hum postdoc, or a good first but not a great second postdoc, and they usually don’t fare well on the market. It is a sad truth that a bad postdoc can totally tank your academic career, especially if it’s the most recent one.The unnerving part is that who you land with is luck to a great degree, so you may be in deep doodoo through very little fault of your own.

I also remember the case of an applicant from a few years ago, who looked great on paper, had a great record from his PhD,  and listed PhD advisor as first reference. The reference letter from the advisor never came, even after reminders. Before you wonder whether the advisor had died, became incapacitated, or was otherwise indisposed, I should tell you that the advisor did submit letters for other candidates in the same search. So the absence of a letter was definitely meant to convey a lack of endorsement. Whether or not this was a petty or a real issue, it hurt the candidate. What is most surprising to me is that the candidate was not aware that there was an issue, that the advisor would not be supportive. Maybe the advisor was sneaky and passive-aggressive, or even openly deceptive — all sweet on the outside but seething with rage and disappointment on the inside. Could it simply be delusion on the part of the candidate, refusing to believe that the advisor  would not provide support? Could it be that everyone’s egos were just a little too big for the candidate’s good?

But, there is no need to sink into the depths of despair at these unfortunate anecdotes. Most PhD and postdoc advisors are really, really supportive of their group alumni. However, some professors are not nice people. Some students are not nice people either. Sometimes there is just too much of a mismatch between what the two parties expect from one another. In an ideal world, the advising relationship would be dissolved in these cases and the junior person would go work for someone more supportive. In an ideal world, people would also talk openly, and the advisor, who holds considerable power over the student/postdoc, would be able to convey what they are unhappy about and what needs to change. But, this is not an ideal world, so you, the candidate, had better rely on your gut and common sense and try to be honest with yourself as to how much support you can realistically expect and from whom during the application process, because the competition is so fierce that committees will readily relegate you to the “do not interview” list if there are doubts cast upon your merit by the people who are supposed to know you best.