Define "health maintenance organization" (HMO).

A health maintenance organization (HMO) is characterized as a type of health insurance plan that emphasizes a network approach to healthcare delivery. This means that members must use a designated group of doctors, hospitals, and other healthcare providers to receive coverage for their medical services. The goal of an HMO is to promote health maintenance and preventative care while keeping costs predictable and manageable through the use of in-network providers.

Members typically select a primary care physician who oversees their healthcare and provides referrals to specialists within the network. This model encourages coordinated care and helps control healthcare expenses. With this structure, the HMO also often offers lower premiums and copayments compared to other plan types, making it an attractive option for many consumers seeking comprehensive healthcare coverage.

In contrast, the other options describe elements that are not representative of HMO structures. Some plans do provide coverage for out-of-network providers at a higher cost, but this characteristic aligns more with preferred provider organizations (PPOs). Similarly, a plan focused solely on emergency services or that covers only preventive services does not encapsulate the full range of HMO services typically provided, which include a broader spectrum of healthcare needs managed within the network.