In an HMO, the primary care physician often serves as a 'gatekeeper,' which means the physician:

Explanation

As a gatekeeper, the primary care physician manages the member's overall care and must generally provide a referral before the member sees a specialist, which helps the HMO control costs and avoid unnecessary services. The gatekeeper does not collect premiums, own the HMO, or set the deductible. The gatekeeper model is a defining feature of traditional HMOs and a key difference from PPOs, which usually let members self-refer to specialists.