Weaknesses in recommendation letters?

In our newest "how can we help you?" thread, a reader writes:

For those who have read letters of reference for job market candidates (both research and teaching): What are some common weaknesses of reference letters? By 'weakness' here I am particularly interested in negative aspects of letters that the applicant might have worked to minimize the likelihood of. For instance, if a common weakness is that the letter doesn't reflect the applicant's research statement, or the letters disagree with each other, this is perhaps something that the applicant could minimize the likelihood of through early and regular communication.

Of course, those who write letters ultimately are responsible for them, and applicants can only do so much to nudge their committee in the 'right' direction. That said, I'd love to hear, from the perspective of the letter readers, what are some tips that might be helpful for applicants when asking their committee for letters.

This is an interesting question, and I'll leave it to readers to interpret in a broad sense. First, we might ask what makes for a weak reference letter in terms of the letter being poorly written, and so not very helpful to a candidate. Second, we might ask what makes for a weak reference letter in the sense of the letter being well-written but nevertheless containing negative information about the candidate. For search committee members: what kinds of 'weaknesses' of reference letters (in any relevant respect) have you commonly come across?

Comments

[reader]

One problem with letters is that they often lack evidence, even thin bits of evidence. Instead, they just praise the applicant. They tell us how great they are. But a good letter should provide evidence for factual claims. "X wrote an important paper on Y, and it will change the debate." Well, isn't that nice to hear. Can you give me any reason to believe you - remember, 200 other people are writing that same damn sentence for their intellectual child.