Demand calculation
From WFM Labs
A simple demand calculation leveraged across the industry to generate an approximate base FTE required is as follows:
Base FTE Required = Call Volume Offered X Average Handle Time / 3600 / Total Annual Work Hours / Occupancy / (1 - Shrinkage)
This calculation can be leveraged to establish a base FTE needed to service an annual workload in order to begin calculating the true costs associated with employee attrition, as described in the High Cost of Attrition