This is a study of how different types of private insurance, indemnity, PPOs, open model HMOs and closed model HMOs affect the use of health services and consumer assessments of care.  This article concludes that the type of insurance that people have, not just whether it is managed care but the type of managed care, affects their use of services and assessments of care they receive.  For example as one moves from indemnity to PPO to open model HMO to closed model HMO, use of primary care increases modestly but use of specialists is reduced; few differences are observed in preventive care, hospital use, and surgeries.  Consumer assessments of care is also looked at.