In letters of recommendation, how are the different percentiles of ability perceived by the admissions committee?

Question

On my letters of recommendation, I was asked to rate if a student was

• Top 1-2%
• Top 5%
• Top 10%
• Top 25%
• Top 50%, or
• Not in the top 50%

The student got an A in my class, and scored in the top 25% of students, class-rank-wise. But I am afraid that if I rate them as "top 25%," and they are applying to a top program, it will make them look like a bad student.

Does the admissions committee discard or look negatively upon all recommendations that aren't top 1-2% or top 5%?

(If it matters, I teach at a top 10 university, so someone who is top 25% here will probably be top 1-2% at a more middling university.)

Answer 1

Great question. It is one of the most ridiculous of all the forms we have to fill out when recommending people. Despite the illusion of being a quantitative measure, in reality it is qualitative and subjective. I imagine most people (certainly in my case) do not do what you have done and actually calculated where the student fell in terms of actual percentage. So if you do the honest thing, and say 25%, you may indeed be putting your student at a disadvantage. I have heard some professors say "oh, anything not top 5% or 10% is code for mediocre student." I'm not defending that view, but it definitely exists and is another symptom of how ridiculous the form is. As the comment by Bryan Krause states, people tend to rate higher, so your student will gain little from your honesty. Top 25% might even be perceived as a red flag. I also agree that admissions committees look at other measures (including the text of the letter) for a better indication of the student's promise.

Answer 2

These questions are typically not asking for percentiles among students in any particular course. Rather they are asking for comparisons among all students you have interacted with. Of course this is also vague and contingent -- in theory, someone who has only interacted with students at absolutely top programs should give lower ratings than someone who had interacted with those same students and also a wider range of students.

Thus I agree that the numerical rating system is too flawed to be taken very seriously. I think it just gets the idea across that recommenders should be thinking about how the recommended student compares to other students at a similar point of their careers and including comparative information.

Giving a student who got an A in your course a "top 25% rating" because their numerical performance is in the top 25% of your course seems to be both an overly literal interpretation of the percentiles and also thinking too narrowly to be helpful. Again, you are not being asked to report on the student's performance in just one course, and if you really know nothing about the student other than the one course they took with you than you are not an especially good person to write a letter for them. How did the student do in other courses at your university? More importantly, how good is a student who gets an A in your course but is not at the very top of the course? Was this student's mastery of the material not as strong as the top students in the course in a way that you think is meaningful in the context of graduate work, or is the situation that you have many excellent students and someone has to come out on top percentage-wise? You also mention that you teach at a top 10 university "if it matters." Yes, it matters! Much as you suggest, it is probably the case that an A student at a top 10 university who is not at the very top of the course compares well with all but the most outstanding students at a lesser university. But it is your job to figure out to what extent that is true and argue for it in the letter.

If you are asking what is usually done on these numerical rankings: most of the letters I receive at my top 50 US math PhD program rank students in the top 10% in most of the categories. Ranking a student in the top 25% across the board will come off as unsupportive unless you explain yourself very carefully in the letter. I think you and the student you recommend will have an easier, better time if you choose among the first three categories in the numerical ratings (the way it works at my program is that students are rated separately on a handful of categories).