Skip to content
ENExplore Calculators

Tracking Signal Calculator

Detect systematic forecast bias using a tracking signal.

About Tracking Signal Calculator

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.

Formula

Tracking Signal

Tracking signal = cumulative signed error ÷ mean absolute deviation

control limit
Conventionally ±4, beyond which bias is considered significant

Worked example

With the default values below, Tracking Signal Calculator returns Tracking Signal of 4.50000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cumulative signed forecast error
180
Mean absolute deviationminimum 0
40
Periods observedminimum 1
12

Results

Tracking Signal
4.50000
Status
Warning — bias is exceeding the control limit
Average Signed Error per Period
15.00000
Conventional Control Limit
4.00
Bias Direction
Forecasts are persistently too low

Step by step

  1. 1Values used
  2. 2Tracking Signal
  3. 3Tracking Signal= 4.50000
  4. 4Status= Warning — bias is exceeding the control limit
  5. 5Average Signed Error per Period= 15.00000
  6. 6Conventional Control Limit= 4.00
  7. 7Bias Direction= Forecasts are persistently too low

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or fees or charges into account.
  • Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Tracking Signal calculated?

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.

Why does Tracking Signal matter?

Tracking signals are the standard automated check in demand planning because they catch bias without human review of every forecast.

What values do I need to enter?

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.

Related Calculators

Tracking Signal Calculator – Calculate Tracking Signal