Evaluation & Quality
Mean absolute error
The average distance between predicted numbers and actual numbers, without separating overestimates from underestimates.
Example
Forecasts miss actual demand by an average of five units.
Why people use it
It gives a typical error size in the same units as the original measurement.
What you'll hear
“The forecast misses by about five units on average.”
What this means for you
Inspect signed errors and important subgroups as well as the average.
Can you control it?
No
No direct control. This describes a wider issue, concept or result rather than something you can simply switch on or off in a tool.
Common questions
- Can two forecasts have the same average error but different worst mistakes?
- Yes. An average can conceal whether the errors are fairly consistent or include a few very large misses.
- Can it show whether predictions are mostly too high?
- No. It treats errors as sizes and does not preserve their direction.
- Does one very large miss dominate it?
- It affects the average, but less strongly than measures that square the errors.