Yes, performance can be based on many different criteria: Patient satisfaction, cost control, mortality rates, patient retention, etc. It depends on the context and what interests you. Patient satisfaction is nice when studying physicians because it's not controversial or liable to provoke strong negative reactions.
Physician is a service a provider and patient is a customer. Customer's satisfaction depends on fulfillment of customer's expectations. In a physician - patient scenario, the patient's expectation could be timely treatment, affordability ( cost ), Quality, Skill & reputation of the physician, compassion etc. Physician's performance could be determined based on his/her ability to manage patient's expectations.
Patient satisfaction, or customer satisfaction, in general can be used as one component of measuring service-provider performance. In healthcare, there is lot of new research showing that patient satisfaction ratings are associated with quality of care outcomes. However, it is also likely that in some cases patients may receive high quality care, but may feel dissatisfied. Thus, patient satisfaction should be one, among may, factors used to determine physician performance. I've inserted a link for one of the papers that documents studies finding an association between patient satisfaction and medical / behavioral outcomes.
Have you asked any US, Veterans Administration Patients? I would be more than willing to discuss this, and I probably know more than a few other patients, about service provider performance. Or it would be reasonably easy to point someone to empirical study results already published. Bear in mind time era results will require evaluation on that basis.