A health maintenance organization (HMO) is a type of managed care organization (MCO) that provides a form of health care coverage that is fulfilled through hospitals, doctors, and other providers with which the HMO has a contract. The Health Maintenance Organization Act of 1973 required employers with 25 or more employees to offer federally certified HMO options. Unlike traditional indemnity insurance, an HMO covers only care rendered by those doctors and other professionals who have agreed to treat patients in accordance with the HMO's guidelines and restrictions in exchange for a steady stream of customers. Benefits are provided through a network of providers. Providers may be employees of the HMO ("staff model"), employees of a provider group that has contracted with the HMO ("group model"), or members of an independent practice association ("IPA model"). HMOs may also use a combination of these approaches ("network model").
The proportion of non-elderly individuals with employer-sponsored cover fell from 66% in 2000 to 56% in 2010, then stabilized following the passage of the Affordable Care Act. Employees who worked part-time (less than 30 hours a week) were less likely to be offered coverage by their employer than were employees who worked full-time (21% vs. 72%).
Some, if not most, health care providers in the United States will agree to bill the insurance company if patients are willing to sign an agreement that they will be responsible for the amount that the insurance company doesn't pay. The insurance company pays out of network providers according to "reasonable and customary" charges, which may be less than the provider's usual fee. The provider may also have a separate contract with the insurer to accept what amounts to a discounted rate or capitation to the provider's standard charges. It generally costs the patient less to use an in-network provider.
California developed a solution to assist people across the state and is one of the few states to have an office devoted to giving people tips and resources to get the best care possible. California's Office of the Patient Advocate was established July 2000 to publish a yearly Health Care Quality Report Card on the top HMOs, PPOs, and Medical Groups and to create and distribute helpful tips and resources to give Californians the tools needed to get the best care.
In addition to medical expense insurance, "health insurance" may also refer to insurance covering disability or long-term nursing or custodial care needs. Different health insurance provides different levels of financial protection and the scope of coverage can vary widely, with more than 40% of insured individuals reporting that their plans do not adequately meet their needs as of 2007.