Abstract
The study described in this article explored the relationships between primary care physician characteristics and patterns of managed care affiliation in a single region. Secondary data sources were used to investigate the affiliations of all primary care physicians in King County, Washington (Seattle and environs) with 29 managed care products in 1996. Descriptive findings indicate that specialty, board certification, and experience all are associated with the managed care affiliations held by physicians. Differences between managed care product provider lists suggest that there are different strategies for the design and management of provider networks.