Telephone calls and appointment requests. Predictability in an unpredictable world.

HMO member-initiated requests for service, including telephone calls and appointments, were studied. Telephone calls to medical offices were found to be directly proportional by a constant factor to the number of members using the facility. The number of member requests for appointments for medical problems and routine physical examinations was also predictable. A method of planning and effectively providing outpatient office appointments is proposed.