US News does kind of have rankings of specialties (IM, Peds, Family med) by school. They don't do it by hospital though. The rankings are about quality of training in the specific specialty in these institutions based on word of mouth by faculty at institutions across the US (i.e., which institutions do you feel deliver the best trained people in this (your) specialty).
It only kind of does because, e.g., they refer to "Harvard" for IM in the top 3 but don't differentiate between MGH/BWH/BIDMC. However, it does offer a good overall picture of how places are considered relative to one another.
Honestly, residency ranking isn't everything. You have to know what you want to do down the road (academic medicine, clinical medicine, etc). The "best" places (i.e., Harvard and others) put out EXCELLENT academicians but not necessarily the best practicing clinicians or the most clinically experienced. I'm not saying they aren't great and the residents aren't extremely well educated. It's a question of what you want.
So take it with a grain of salt, especially when you hear about things by word of mouth. Just because institution A seems like the best in one person's eyes doesn't mean it's the best for you.
