<p>Hi, </p>
<p>I'm in the process of assigning rec letters to my mentor, but I noticed that different schools require you to assign a recommender differently. Does this mean that different schools have different requirements for the recommendation, or would one letter from my mentor suffice for all of them? Specifically for Stanford, Caltech, UPenn, Cornell, and Carnegie Mellon, that is!</p>
<p>Additionally, what IS the mentor recommendation? Is it a series of questions? Does the mentor simply upload a letter to the website? Do they have to mail the letter in?</p>