They are licensed at the state level, under a license that is known as a certificate of authority (COA), rather than under an insurance license. In 1972, the National Association of Insurance Commissioners adopted the HMO Model Act, which was intended to provide a model regulatory structure for states to use in authorizing the establishment of HMOs and in monitoring their operations. In practice, an HMO is a coordinated delivery system that combines both the financing and the delivery of health care for enrollees. In the design of the plan, each member is assigned a "gatekeeper", a primary care physician (PCP) responsible for the overall care of members assigned. Specialty services require a specific referral from the PCP to the specialist. Non-emergency hospital admissions also require specific pre-authorization by the PCP. Typically, services are not covered if performed by a provider not an employee of or specifically approved by the HMO unless it defines the situation to be an emergency.