One NE program at a top medical school receives about 100-150 applications each year and interviews about 20 non-home school applicants. There is also an internal competition from the medical school's own ranks, but that is separate from the external competition. There are usually 30 students competing for the internal spots.
The general admission is about 5-6 external spots and 3 internal spots.
The evaluation of applications considers all things, including MCAT scores, transcripts, and dean's letters.
In addition to proposed mentor (reputable, proven track record of mentorship, enthusiastically wants you at the program... their strong recommendation is hugely important), I think the next most important attribute of your application (given that your application is competitive) is whether you fit the program. Are you interested in a field where program X has few resources and few individuals of expertise? Every program is unique and the most often cited flaw is "poor fit." For example, if it is obvious that you are a future HHMI researcher (basic science) instead of a translational or clinical researcher, then they will be less likely to take you in a Doris Duke program. And then I'm sure there are a dozen other ways "poor fit" may happen.
Hope this helps! Good luck!
