Reference

Forecast accuracy

How close the contact volume forecast came to what arrived, measured interval by interval.

Also called: WAPE, MAPE, forecast error.

Why it matters

Every schedule is built on the forecast. A miss in a busy interval shows up as long waits or idle agents.

WAPE: Sum over intervals of |actual − forecast| ÷ sum of actual contactsThe volume-weighted error: every contact missed counts once, above or below. Staffing is planned on this.As published in the Forecast Accuracy Tracker method, version 1.0.
Interval accuracy: 1 − WAPEThe headline. It falls below zero only when contacts missed exceed the contacts that arrived.As published in the Forecast Accuracy Tracker method, version 1.0.
Tracking signal: Sum of (actual − forecast) ÷ mean absolute errorWhether the errors lean one way. Read against the limit below.As published in the Forecast Accuracy Tracker method, version 1.0.

Accuracy on the total for a day or a month lets interval misses cancel out, so it can look excellent while intervals miss badly.
MAPE weights a miss in a quiet interval as heavily as one in a busy interval; WAPE weights by volume.
A forecast that is always high or always low has a bias to fix, which accuracy alone does not show.

No published figure for this measure passes our source rules, so none is shown.