number of letters of recommendation

[ChemEnthusiast]

Hey guys I am wondering about the number of letters that you can submit. Most schools require 3, but I have 4. Does it really matter if I submit one extra letter?

[AkashSky]

Some schools don't allow it but generally the fourth letter is fine.  Some even have it optional.  Essentially, if the schools you are applying to allow it, you should submit it.

[ChemEnthusiast]

Thank you for your reply!

[St Andrews Lynx]

I'd stick with 3.

You want recommendation letters from professors that know you well and who can testify about your suitability for grad school (ideally through talking about your research experience, but from graduate-level coursework classes is OK too). Prioritise the 4 letter writers you have and leave out the weakest.

Your fourth letter may just be ignored. Or worse, the AdComm will look at it and go "Jeez, we specifically asked for 3 letters and they gave us 4. This person doesn't follow instructions..."

[fuzzylogician]

I think it's generally fine to submit 4 if the system allows it and there is no text that says not to do it. However, only submit this extra letter if it is as strong as the other letters. Additional materials should be there for a reason, since you're creating extra work for your readers. 

15 minutes ago, St Andrews Lynx said:

Your fourth letter may just be ignored. Or worse, the AdComm will look at it and go "Jeez, we specifically asked for 3 letters and they gave us 4. This person doesn't follow instructions..."

Or worse -- one of your original 3 might be ignored instead of your extra letter. This is why this extra letter has to be at least as strong as the others. 

[ChemEnthusiast]

Thank you for your input, do you think removing this 4th letter would be a wise choice? Three of my letters come from professors that I have done research with and this one come from my boss/ professor who I took a class with and later become a TA for that class. I put him on the application because he can comment on my ability as a TA.

[fuzzylogician]

10 minutes ago, ChemEnthusiast said:

Thank you for your input, do you think removing this 4th letter would be a wise choice? Three of my letters come from professors that I have done research with and this one come from my boss/ professor who I took a class with and later become a TA for that class. I put him on the application because he can comment on my ability as a TA.

Imagine this not unlikely scenario: the letters in applicants' files are ordered by their submission date, not by whether the applicant ranked them as 1/2/3/4. A professor picks up the file, see 4 letters, and decides: "we required three letters. Therefore, I will only read the first three letters in this file" (or: the prof reads the first three letters, unexpectedly encounters a fourth, and decides to skip it). Will you be okay with any 3 of the 4 being read, or will it make your application weaker if this 4th letter is read instead of one of the original 3? If it would be all the same, you could include it. If it would make the application weaker, that is an argument against including it. 

[St Andrews Lynx]

TA-ing experience is moderately nice to have...but a lack of it doesn't penalise applicants. Some people in my cohort had TA experience before they joined the program, but plenty didn't (including myself) and we were all treated the same way. For Chemistry PhDs, the research experience is what really matters. For that reason, I'd just leave out the 4th "teaching" letter.

[ChemEnthusiast]

Thanks for great answers guys, I will take this into consideration for my next applications.