Author Affiliations: The Robert Graham Center, Washington, DC (firstname.lastname@example.org).
To the Editor: Decades of ecologic evidence linking primary care and decreased cost1 have been challenged by recent studies,2 including the recent study by Dr Chang and colleagues.3 This study linked individual Medicare beneficiary claims data to physicians and assessed 3 key health outcomes while ecologically accounting for patient, population, and other workforce characteristics within primary care service areas. This improves on previous studies by connecting beneficiaries and their outcomes directly to physicians. The study also tested the limitations of the American Medical Association (AMA) Masterfile count of primary care physicians by using Medicare claims data to assign full-time equivalents.
Phillips RL, Petterson SC, Bazemore AW. Primary Care Physician Workforce and Outcomes. JAMA. 2011;306(11):1201-1202. doi:10.1001/jama.2011.1324