In Health Maintenance Organizations (HMOs), the use of a primary care physician or PCP is common as part of

The group model refers to a structure where an HMO contracts with a group of physicians to provide care to its members. While this model can encompass primary care physicians, it does not specifically highlight the role of the PCP as a gatekeeper in managing referrals and care, which is the core principle of the gatekeeper concept.

Using an out-of-network provider involves accessing healthcare services from providers who are not contracted with the HMO. In this scenario, patients typically face higher costs and limited coverage, which contradicts the gatekeeper concept where a PCP coordinates care within the network to maximize efficiency and minimize expenses.

Open enrollment is a designated period during which individuals can enroll in or make changes to their health insurance plans. While it pertains to HMO membership, it does not relate to the role of the primary care physician as a gatekeeper for accessing healthcare services.