What is a characteristic feature of an HMO?

A characteristic feature of a Health Maintenance Organization (HMO) is the strict requirement to use network providers for coverage. This means that members must select a primary care physician (PCP) from the HMO's network and obtain referrals to see specialists, which helps to manage care and costs effectively. The design encourages members to use a specific group of healthcare providers, ensuring that care is coordinated through the primary care physician. This structure is intended to maintain lower overall healthcare costs and promote preventive care within the network.

In contrast, open access to specialists without a referral typically pertains to Preferred Provider Organizations (PPOs), where members have more flexibility in choosing healthcare providers. Fixed costs for healthcare services regardless of use may apply to various insurance plans or payment structures but do not specifically define the HMO model. The option regarding insurance being available only for individual purchases does not accurately represent HMOs, as they can offer both individual and group plans.