One PD at an a school that I interviewed at told me that if their school was their top choice, I could let them know by e-mail. My home school suggested that I schedule a meeting with my PD after I finished interviewing just so that they could see "what they could arrange". It's BS, it's actually illegal for PD's to ask you where you plan to rank them, but some do find ways around them. I've heard of one student who sent a LOI to one program and she received a letter back saying that although they couldn't officially tell her where they were going to rank her, they looked forward to working with her next year. I think that LOI's do play some role in where programs decide to rank you. One chief resident explained it to me in that if a program knows that you are really enthused about their program, you will be more likely to do a good job and complete residency at their program (drop-outs area huge pain for programs). I think PD's get together and compare how low they had to go on their rank list too, just as a sign of prestige of the program or something, no one wants to say to other PD's that they ended up with the bottom 20 of their rank list I guess. My thought is that it may push you up a notch or two on their rank list, and even if it doesn't, it's not going to hurt to send one. One program that I sent an e-mail of interest to sent me 2 hand-written post cards thanking me for visiting. I know that doesn't mean I'll be put high on their rank list, but I hope that it means that they will at least be ranking me somewhere or else they wouldn't have bothered sending out the post-cards. I'd go ahead and do it. The worst that could happen is that they could just throw it away once it arrived.
