@OP A possible reason that private medical schools on the whole place more emphasis on research is that there are more research heavy private schools than there are public schools which skews the data for this particular survey. However, research is fairly important for all medical schools, and if you look on MSAR, most schools say that ~90% of their matriculants participated in research prior to medical school with even the lowest amounts being more than 2/3 of a school's class. I would say that research is pretty much a de facto requirement for a serious applicant at this stage, even if its just a summer or a semester.
