Drawing on a nationally representative survey of physicians, this pape
r examines the extent to which physicians split their time between pri
mary care and non-primary care activities and whether managed care mak
es a difference. We find that managed care does matter: Physicians hav
e been narrowing their scope of practice, and the trend is linked to t
heir involvement with managed care plans. These findings have implicat
ions for workforce policy and training, regulation of managed care con
tracting, and the quality of care.