While most insured Americans obtain health coverage through the private sector, public entities play an increasingly significant role. Definitions and Principles

People buy insurance to protect themselves against the possibility of financial loss in the future. Health insurance provides protection against the possibility of financial loss due to high health care expenses. Also, people do not know ahead of time exactly what their health care expenses will be, so paying for health insurance on a regular basis helps to smooth out their spending. 104-191 ), and the Patient Protection and Affordable Care Act (ACA; P.L. 111-148 , as amended). Sources of Health Insurance

Americans obtain health insurance through a variety of methods and from different sources (see Figure 1 ). In 2013, a majority (64.2%) of Americans obtained health insurance through the private sector, which includes both employer-sponsored and nongroup coverage. Public programs (Medicare, Medicaid/CHIP, or health care services for military servicemembers and veterans) provided coverage to 34.3% of Americans. Approximately 13.4% of Americans were uninsured for the entire year of 2013. , 
Within each of the sources, health insurance differs by the market structure itself—group versus nongroup, fully insured versus self-insured; self-only versus family coverage, etc. Those arrangements vary due to numerous factors such as how health care is financed, how much access to providers and services is controlled, and how much flexibility the enrollees have to use the services covered under her/his health plan. In this model of health care delivery, the financing of health services and the obtaining of those services are kept separate. One example that is at the heart of discussions about consumer-driven care is the health savings account (HSA).
People obtain insurance to protect themselves against the possibility of financial loss in the future. Health insurance provides protection against the possibility of financial loss due to high health care expenses. Also, people do not know ahead of time exactly what their health care expenses will be, so paying for health insurance on a regular basis helps ease their out-of-pocket spending.
While health coverage continues to be mostly a private enterprise in this country, government plays an increasingly significant role. Government has initiated and responded to dynamics in medicine, the economy, and the workplace through legislation and public policies. One of the most recent efforts was enactment and ongoing implementation of the Patient Protection and Affordable Care Act (ACA; P.L. 111-148, as amended). ACA includes provisions to encourage the expansion of health insurance coverage, and establish new federal health insurance standards, among other reforms.
Americans obtain health insurance in different settings and through a variety of methods. In 2013, a majority (64.2%) of Americans obtained health insurance through the private sector, which includes both employer-sponsored and individual market coverage. Public programs (Medicare, Medicaid/CHIP, or health services for military servicemembers and veterans) provided coverage to 34.3% of Americans. Approximately 13.4% of Americans were uninsured for the entire year of 2013.
Health insurance benefits are delivered and financed under different systems. The factors that distinguish one delivery system from another are many, including how health care is financed, how much access to providers and services is controlled, and how much authority the enrollee has to design her/his health plan. To illustrate, managed care is characterized by predetermined restrictions on accessing services and providers, whereas individual decision-making regarding use of health benefits is a hallmark of consumer driven health care, such as health savings accounts. As economic conditions change, a specific delivery system may gain or lose the interest of affected parties.