Obtaining a Physician Through a Hospital

Some hospitals advertise asking people to contact it for the name of a physician to treat their illnesses. I think the hospital then provides the name of a doctor who is associated with the hospital. I'm not sure if the doctor pays for each referral or how it worke.

I think some of the doctors have their offices outside the physical hospital (i.e., private practice). Others I believe see the patient within the hospizal building.

My question is, is there a reason for me as a patient to insist on a doctor whose office is at the hospital? I want the most capable physician. I thought the doctors at the hospital might be better but I'm not sure.