By the numbers. Insurers/managed care.
D054598:Blue Cross Blue Shield Insurance Plans / Q000706:statistics & numerical data; D019538:Health Care Surveys; D006279:Health Maintenance Organizations / Q000706:statistics & numerical data; D006801:Humans; D007348:Insurance, Health / Q000706:statistics & numerical data*; D008329:Managed Care Programs / Q000458:organization & administration / Q000706:statistics & numerical data*; D011243:Preferred Provider Organizations / Q000706:statistics & numerical data; D014481:United States