Health insurance offers financial protection in the event of a major medical need. It allows individuals to access hospitals and healthcare providers within a network, and it often covers pre-existing conditions after a waiting period. It can be purchased for one person or for an entire family. Some policies are lifetime renewable, which can save on premiums and provide uninterrupted coverage.

The availability of health insurance is a fundamental economic and social issue in the United States. In spite of the longest economic expansion in history, one in six Americans lacks health insurance coverage. This article aims to refocus attention on the issue, with an emphasis on understanding why people go without coverage and how public policy can help.

Many of those who go without health insurance do so because they cannot afford it. However, others do so because of nonfinancial barriers that prevent them from receiving care. These can include a lack of transportation or illiteracy, as well as cultural and linguistic factors. Moreover, for many who do have health insurance, the cost of their coverage is too expensive to allow them to use it regularly.

While the Affordable Care Act has largely eliminated the problem of uninsurance, it does not eliminate the problem of underinsurance. Individuals can be underinsured even if they have a health insurance plan that provides extensive out-of-pocket costs, such as copayments, deductibles, and maximum benefit limits. Those with health insurance can still be underinsured if their plan does not cover specific services, such as mental healthcare or long-term care.

There are several ways to acquire health insurance coverage: through employment, government programs, or private insurance. Almost seven out of 10 adults have employment-based coverage, and most of them choose to purchase it through their employer. However, young workers and those who are self-employed often do not accept workplace offers of health insurance. Those who do not have employment-based coverage or choose to decline it can obtain health insurance through the marketplaces established by the Affordable Care Act.

Depending on their needs and budget, consumers can choose from among four levels of coverage offered by the health marketplaces: bronze, silver, gold, and platinum. The marketplaces also offer a fifth category, called catastrophic, for those with the lowest incomes. The prices of the plans vary, but they all require a monthly payment, called a premium, and may have additional out-of-pocket costs, such a copayments or coinsurance.

Whether they are sold on the exchanges or outside them, all major medical health insurance plans must comply with the Affordable Care Act and be guaranteed-issue, meaning that insurers can not discriminate against applicants based on their past medical histories. Nevertheless, a number of other factors, such as changes in income or the terms of employment, can trigger the loss or gain of health insurance. In addition, people can move between the different categories of coverage only during open enrollment periods or special enrollment periods triggered by qualifying events.