I wasn't aware it was "generally accepted." Most graduate programs don't like to poach from their own undergrad school. I was wondering if Med school to Residency had the same taboo. I guess not. Thanks.
I've found that the in the medical arena, preference is given for applicants the programs know with more certainty that they are good workers. It's sometimes risky to gamble on applicants they only know about from the application. (on the flip side this may also be why sometimes nepotism occurs with some frequency in this field unfortunately). It's easier for faculty to get to "know" how good a resident/future fellow is from watching them work for 3 years (or 5 years if you also did med school there). The longer you stay at an institution, the more opportunities you have of building your reputation as a hard worker and showing how "good" you are. Word of mouth, just as with residency quality, also works that way for residenT quality. If you go to a new place, you have to prove yourself all over again, even if you do get accepted. So often, applicants prefer to stay at the same institution for fellowship because of that.
And you're right, often graduate programs (especially in biology and chemistry) are against accepting their own (which I think is weird personally, but i suppose makes sense if they want to mix the pool of knowledge
😛 ). Medicine is definitely different that way, because how you work is more important. The knowledge is the same everywhere, since most of medical learning is self-taught.
As for the residency quality ranking, i agree with what other posters have said, re: a lot of it being by word of mouth at least as far as malignant vs. friendly programs go. Furthermore, even among the good programs, ranking of quality is actually very individual, based on your own personal career goals and preferences, because even the strong programs have different focuses, special strengths, overall attitude, etc that you should decide for yourself about what the best fit for YOU would be. So actual order is very applicant dependent and not to be quantified into a single rank list for all.