Lettering

At Scatterplot, Shamus Khan wonders about writing letters of rec for multiple students in the same field:

What’s the best strategy here? Do you just send a letter out for each student and not mention the letters you’ve written for other students?

What’s the right thing to do by the students? Should you counsel students so they don’t apply to the same jobs? In some ways it depends on the situation. Either, (1) you really think the students are pretty comparable and it is a matter of fit with a particular job, OR (2) you really think one of them is significantly better than the other, at least for top jobs.

I agree with the commenters who have already raised the issue of that most mysterious of all hiring practices--the search for the elusive "fit."  Given just how much luck is involved, it's best not to predict which student will have more appeal to which hiring committee.  One thing I would suggest if you're writing multiple letters, though: for crying out loud, don't say "this is the best student I've ever had!" in every letter you write.  Yes, I've seen such things while on committees, and no, I wasn't impressed.    All job applicants magically become brilliant during the hiring season (to the extent that any hint of negativity becomes a red flag); unless this truly is the bestest, awesomest, superduperest candidate you've ever seen, it's much better to stick to a very specific assessment of his/her strengths and scholarly potential.