Models of managed care: the potential power of the IPA.

As managed care changes medical practice organization, Individual or Independent Practice Associations (IPAs) have theoretically superior attributes as compared with the more centralized large integrated multispecialty group on the one hand, and the less centralized "direct gatekeeper" model on the other. IPAs preserve the small, entrepreneurial, efficient, personal practice model of care delivery, while grafting on necessary business, informational, and care rationalizing functions at the collective level. The IPA also offers practitioners political leverage against the centralizing forces, particularly if the IPA establishes multiple HMO and PPO relationships. Physician autonomy will be best served if practices are allowed multiple IPA memberships. Competition in this model will be multicentric.