Daily number of clinic appointments (filled and unfilled).

The wait time for an appointment is the difference between when the demand for that appointment is declared and when the supply is applied.  Therefore, it is important to understand supply and demand for appointments when trying to improve delays for appointments. 

Supply refers to the total resources (people, equipment, offices and exam rooms) available to a clinic.  When the total resources are managed well, a clinic creates openness in its schedule or space to care for patients.

Patients experience this openness primarily as the availability of clinic appointments.  Since, in most systems, clinician time for appointments is the bottleneck, capacity is the total hours of clinician time devoted to appointments.