Managed care is a system of health care delivery that aims to provide health care that is cost-effective, accessible, and of high quality. The popularity of managed care has grown tremendously in the United States in the past decade in response to demands by payers (employers and government) that these aims be met, particularly that of cost containment. There are now more than 58 million people enrolled in approximately 575 health maintenance organizations (HMOs) and millions more in the other two prominent types of managed care organizations (MCOs): preferred provider organizations (PPOs) and managed fee-for-service (FFS) plans. <sup>11 Kertesz L., Lutz S., Sloane T. Sorting out the stories that mattered Modern Healthcare 1996 ;  26 : 44

Cliccare qui per andare alla sezione Riferimenti</sup> The percentage of workers in private companies who enrolled in some form of managed care increased from 29% in 1988 to 70% in 1995. <sup>12 Peat Marwick K.P.M.G.   Health Benefits in 1995 Washington, DC: KPMG Peat Marwick (1995). 

Cliccare qui per andare alla sezione Riferimenti</sup> As a result of this change, employer spending on health benefits increased only by 0.1% from June 1995 to June 1996, <sup>20 US Department of Labor   A Look at Employers' Cost of Providing Health Benefits Washington, DC: US Department of Labor (1996). 

Cliccare qui per andare alla sezione Riferimenti</sup> and the rise in national health care costs slowed to the lowest rate in three decades. <sup>13 Levit K.R., Lazenby H.C., Sivarajan L. , e al. National health expenditures, 1994 Health Care Financ Rev 1996 ;  17 : 205

Cliccare qui per andare alla sezione Riferimenti</sup> In addition, major shifts to managed care are underway in the Medicare and Medicaid programs.

Although the increasing emphasis on managed care has been fueled by changing demands in the marketplace and the health care reform debates of 1993 and 1994, the concepts are far from new. In this article, a review of the evolution of managed care and an explanation of its distinguishing features set the stage for more in-depth presentations of specific managed care topics in subsequent articles in this issue.