The Commonwealth Fund, in its annual survey, "Mirror, Mirror on the Wall", compares the performance of the health care systems in Australia, New Zealand, the United Kingdom, Germany, Canada and the U.S. Its 2007 study found that, although the U.S. system is the most expensive, it consistently under-performs compared to the other countries.[6] One difference between the U.S. and the other countries in the study is that the U.S. is the only country without universal health insurance coverage.
The share of Americans without health insurance has been cut in half since 2013. Many of the reforms instituted by the Affordable Care Act of 2010 were designed to extend health care coverage to those without it; however, high cost growth continues unabated.[3] National health expenditures are projected to grow 4.7% per person per year from 2016 to 2025. Public healthcare spending was 29% of federal mandated spending in 1990 and 35% of it in 2000. It is also projected to be roughly half in 2025.[4]
Broader levels of health insurance coverage generally have higher premium costs. In many cases, the insured party is responsible for paying his/her healthcare provider an up-front, tax deductible amount called co-pay. Health insurance companies then may compensate healthcare providers directly or reimburse the policy holder based on the remaining portion of an itemized bill.
According to some experts, such as Uwe Reinhardt,[120] Sherry Glied, Megan Laugensen,[121] Michael Porter, and Elizabeth Teisberg,[122] this pricing system is highly inefficient and is a major cause of rising health care costs. Health care costs in the United States vary enormously between plans and geographical regions, even when input costs are fairly similar, and rise very quickly. Health care costs have risen faster than economic growth at least since the 1970s. Public health insurance programs typically have more bargaining power as a result of their greater size and typically pay less for medical services than private plans, leading to slower cost growth, but the overall trend in health care prices have led public programs' costs to grow at a rapid pace as well.

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.[2]