The productivity of physician assistants and nurse practitioners and health work force policy in the era of managed health care.

Managed care is spreading rapidly in the United States and creating incentives for physician practices to find the most efficient combination of health professionals to deliver care to an enrolled population. Given these trends, it is appropriate to reexamine the roles of physician assistants (PAs) and nurse practitioners (NPs) in the health care workforce. This paper briefly reviews the literature on PA and NP productivity, managed care plans' use of PAs and NPs, and the potential impact of PAs and NPs on the size and composition of the future physician workforce. In general, the literature supports the idea that PAs and NPs could have a major impact on the future health care workforce. Studies show significant opportunities for increased physician substitution and even conservative assumptions about physician task delegation imply a large increase in the number of PAs and NPs that can be effectively deployed. However, the current literature has certain limitations that make it difficult to quantify the future impact of PAs and NPs. Among these limitations is the fact that virtually all formal productivity studies were conducted in fee-for-service settings during the 1970s, rather than managed care settings. In addition, the vast majority of PA and NP productivity studies have viewed PAs and NPs as physician substitutes rather than as members of interdisciplinary health care teams, which may become the dominant health care delivery model over the next 10-20 years.