Procurement & Supply Chain / Demand Planning
Forecast Accuracy & Bias ~ (aliases: MAPE, WMAPE/WAPE, MAD, forecast error, tracking signal)
How close the demand forecast came to actual demand, both the size of the error and whether it leaned consistently high or low.
The fork, why two teams get different numbers
Accuracy and bias are different questions confused under one "forecast accuracy" number.
In the Metric Library
- The full fork, both definitions worked all the way through
- The trap that makes the number lie, on a real export
- Every formula variant, spelled out
- The reconciliation anchor, what to tie it to and when to refuse
Reference: APICS/SCOR (Forecast Accuracy) · IBF (Institute of Business Forecasting)