HMO (Health Maintenance Organization) - Offers healthcare services only with specific HMO providers. Under an HMO plan, you might have to choose a primary care doctor. This doctor will be your main healthcare provider. The doctor will refer you to other HMO specialists when needed. Services from providers outside the HMO plan are hardly ever covered except for emergencies. 
Bärnighausen, Till; Sauerborn, Rainer (May 2002). "One hundred and eighteen years of the German health insurance system: are there any lessons for middle- and low income countries?" (PDF). Social Science & Medicine. 54 (10): 1559–87. doi:10.1016/S0277-9536(01)00137-X. PMID 12061488. Retrieved 10 March 2013. As Germany has the world's oldest SHI [social health insurance] system, it naturally lends itself to historical analyses.
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.[94] 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").[19][95]
The first government responsibility is the fixing of the rate at which medical expenses should be negotiated, and it does so in two ways: The Ministry of Health directly negotiates prices of medicine with the manufacturers, based on the average price of sale observed in neighboring countries. A board of doctors and experts decides if the medicine provides a valuable enough medical benefit to be reimbursed (note that most medicine is reimbursed, including homeopathy). In parallel, the government fixes the reimbursement rate for medical services: this means that a doctor is free to charge the fee that he wishes for a consultation or an examination, but the social security system will only reimburse it at a pre-set rate. These tariffs are set annually through negotiation with doctors' representative organisations.
Medicare Advantage plans expand the health insurance options for people with Medicare. Medicare Advantage was created under the Balanced Budget Act of 1997, with the intent to better control the rapid growth in Medicare spending, as well as to provide Medicare beneficiaries more choices. But on average, Medicare Advantage plans cost 12% more than traditional Medicare.[48] The ACA took steps to align payments to Medicare Advantage plans with the cost of traditional Medicare.
On the whole, uninsured Americans have worse health outcomes; cancers and other deadly diseases, for example, are more likely to be diagnosed at later stages in uninsured people. Uninsured pregnant women use fewer prenatal services and uninsured children and adults are less likely than their insured counterparts to have a primary care doctor whom they trust.
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Health insurance companies are not actually providing traditional insurance, which involves the pooling of risk, because the vast majority of purchasers actually do face the harms that they are "insuring" against. Instead, as Edward Beiser and Jacob Appel have separately argued, health insurers are better thought of as low-risk money managers who pocket the interest on what are really long-term healthcare savings accounts.[131][132]
An employee who needs to request an exemption from the required enrollment in the HIP HMO Preferred Plan can do so by submitting an Opt-Out Request Form to EmblemHealth. An employee, or eligible dependent, must meet certain criteria and the request must be approved by EmblemHealth before the exemption is granted. The Opt-Out Request Form is available on the EmblemHealth website. 
Medicaid was instituted for the very poor in 1965. Since enrollees must pass a means test, Medicaid is a social welfare or social protection program rather than a social insurance program. Despite its establishment, the percentage of US residents who lack any form of health insurance has increased since 1994.[51] It has been reported that the number of physicians accepting Medicaid has decreased in recent years because of lower reimbursement rates.[52]

According to a 2000 Congressional Budget Office (CBO) report, Congress passed legislation creating "two new vehicles Association Health Plans (AHPs) and HealthMarts, to facilitate the sale of health insurance coverage to employees of small firms" in response to concerns about the "large and growing number of uninsured people in the United States."[82]

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.
Public insurance cover increased from 2000–2010 in part because of an aging population and an economic downturn in the latter part of the decade. Funding for Medicaid and CHIP expanded significantly under the 2010 health reform bill.[9] The proportion of individuals covered by Medicaid increased from 10.5% in 2000 to 14.5% in 2010 and 20% in 2015. The proportion covered by Medicare increased from 13.5% in 2000 to 15.9% in 2010, then decreased to 14% in 2015.[3][10]