As a former educator, I have to warn against putting too much stock in this info. While it is smart to be cautious of programs with a very poor pass rate, like 60%, having a high pass rate tells you very little about the quality of the program.
Just like schools can, residency programs can "teach to the test" to improve their scores. For residents this can mean lots of time spent in lectures or review type courses that are less useful in the long run than a good solid educational base.
The scores also reflect, to some degree, just the quality of test takers in the program. If the program focuses more on numbers, like Step scores, for their admission choices, it can artificially elevate their pass rate without improving the quality of pedi education and experience for their residents.
I would be somewhat cautious as well of a program that has a less than 60% pass rate, or even lower. I would guess that the pediatrics boards, at least from the review books I have seen, do test the fundamental knowledge that a pediatric resident has to know to be a good pediatrician. I think there is a tendency for medical schools who don't do well with preparing their students for the boards to absolve themselves from lower scores or a relatively large number of failing students by saying well, "we don't teach for the boards, we give you a solid education that will help you to be a better doctor." I would say that if a student/resident has a good solid educational base then they will easily pass the boards/usmle step exams. If as a resident I failed the peds board exam, I would question whether I had truly learned enough to be a good pediatrician, even if I went to Boston's Children's residency program.
When I studied for my usmle I had to learn alot of the material from a different perspective, and felt that the school did a poor job of presenting the material in a structured format and missed alot of new or important information. It matters alot whether the lectures are well prepared or if a resident presents a new patient to an attending who just tries to muddle through the management process, congraulates their team, and spends 15 minutes out of the hour telling jokes! There are many lectures in medical school that I could have better spent my time reading a well-prepared book.
I think to do well on the usmle/boards you need to be an independent thinker and utilize sources of information outside your syllabus for medical school or residency. I think that studentdoctor.net is a good source of information about what are good books, and reading e-journals is a good way to stay uptodate. Schools/residency programs emphasize different aspects, and often one topic that is well covered at one place won't be covered at all at another, so it is up to the student/resident to figure out what their institution is glossing over, as well as to identify their own weakness points. My pet project, probably never to be realized, would be to create an electronic national medical student syllabus, with hyperlinks to journal articles, something which could be updated by experts in the field every couple of months, and would be heavily edited by several schools during the year, and have lots of pictures.
A pass rate of 90% for a program like Boston's Children's tells me alot, especially since supposedly a large number of these residents did very well on usmle and pediatric clerkship shelf exam. One possibility is that the lectures at boston's childrens are not well prepared, or of low quality, or not frequent enough. Another is that residents need time to rest and digest, i.e. too busy call schedules may interfer with learning objectives to a certain degree, however, I would suspect that all programs have a similar call schedule. However, barring unusual circumstances, I would not say that a resident at Boston Childrens who failed the board examinations is better prepared to be a pediatrician than a resident at another pediatric residency who passed with flying colors, just because the resident at Boston Childrens was in a supposedly great teaching environment. The PD at Boston Childrens should look at what area of the Peds Board the residents are weakest in and figure out how to buff up this part of the education.
Very important for studying for boards and in medicine is the concept of meta-cognition, i.e. being aware of what area of medical knowledge you are deficient in. If I have a peds patient in the ED and they have a presentation of a disease that I don't pick-up, or I don't know the answer immediately to a question, then I go back that day to the library or internet to figure out where the holes in my knowledge are. I think this is important for being a good doctor too, as you always need to have a certain level of curiosity about finding out what you don't know. However, some programs and schools change their syllabus very infrequently, and don't figure out how to teach old material from a new perspective, hence it becomes stagenant. The residents at Boston Childrens might be the victims of such a stagnant learning environment.