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.
Health insurance is a benefit provided through a government agency, private business, or non-profit organization. To determine cost, a provider estimates collective medical expenses of a population, then divides that risk amongst the group of policy subscribers. In concept, insurers recognize that one person may incur large unexpected expenses, while another may incur none. The expense, then, is spread among a group of individuals to make health care more affordable for the common good of all. In addition, public health programs like Medicare, Medicaid, and SCHIP are federally-funded and state-run to provide additional medical coverage to those in vulnerable groups who qualify, such as seniors and those with disability.
The UK's National Health Service (NHS) is a publicly funded healthcare system that provides coverage to everyone normally resident in the UK. It is not strictly an insurance system because (a) there are no premiums collected, (b) costs are not charged at the patient level and (c) costs are not pre-paid from a pool. However, it does achieve the main aim of insurance which is to spread financial risk arising from ill-health. The costs of running the NHS (est. £104 billion in 2007-8) are met directly from general taxation. The NHS provides the majority of health care in the UK, including primary care, in-patient care, long-term health care, ophthalmology, and dentistry.
Medicare Supplement policies are designed to cover expenses not covered (or only partially covered) by the "original Medicare" (Parts A & B) fee-for-service benefits. They are only available to individuals enrolled in Medicare Parts A & B. Medigap plans may be purchased on a guaranteed issue basis (no health questions asked) during a six-month open enrollment period when an individual first becomes eligible for Medicare. The benefits offered by Medigap plans are standardized.
Health insurance programs allow workers and their families to take care of essential medical needs. A health plan can be one of the most important benefits provided by an employer. The Department of Labor's Health Benefits Under the Consolidated Omnibus Budget Reconciliation ACT (COBRA) provides information on the rights and protections that are afforded to workers under COBRA.
Health insurance in the United States is any program that helps pay for medical expenses, whether through privately purchased insurance, social insurance, or a social welfare program funded by the government. Synonyms for this usage include "health coverage", "health care coverage", and "health benefits". In a more technical sense, the term "health insurance" is used to describe any form of insurance providing protection against the costs of medical services. This usage includes private insurance and social insurance programs such as Medicare, which pools resources and spreads the financial risk associated with major medical expenses across the entire population to protect everyone, as well as social welfare programs like Medicaid and the Children's Health Insurance Program, which both provide assistance to people who cannot afford health coverage.