HMOs and PPOs in review.

The significance of the growth of health maintenance organizations (HMOs) and preferred provider organizations (PPOs) hinges on the reliability of the reported figures, which may not be accurate. The greatest changes in the industry over the past 3 months were evidenced in the areas of federal legislation regarding Medicare beneficiaries and military personnel, and within the industry itself, with numerous joint ventures and acquisitions. Dynamic changes continue, and the actors are becoming more clearly defined.