Detect systematic forecast bias using a tracking signal.
Random errors cancel over time so the cumulative signed error stays near zero. A tracking signal drifting beyond ±4 indicates the model is systematically wrong rather than merely imprecise. Tracking signals are the standard automated check in demand planning because they catch bias without human review of every forecast.
Tracking Signal
Tracking signal = cumulative signed error ÷ mean absolute deviation
Tracking signal = cumulative signed error ÷ mean absolute deviation Random errors cancel over time so the cumulative signed error stays near zero. A tracking signal drifting beyond ±4 indicates the model is systematically wrong rather than merely imprecise.
Tracking signals are the standard automated check in demand planning because they catch bias without human review of every forecast.
This calculator takes 3 inputs: Cumulative signed forecast error, Mean absolute deviation, Periods observed. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.