Mean Absolute Percentage Error (MAPE)#
The average absolute error expressed as a percentage of actuals.
Important
✨ AI-generated content. This page was written with the assistance of an AI language model and is provided as a learning aid. Despite careful review, it may still contain mistakes, omissions, or out-of-date information. Whether you are new to the topic, a team lead, or a senior practitioner, treat it as a starting point rather than an authoritative reference: read it critically and independently verify anything you act on (code, commands, figures, and factual claims) against official documentation and primary sources before relying on it.
What it is#
Mean absolute percentage error expresses each error as a percentage of the actual value, averaged:
This makes it scale-free — comparable across series of wildly different magnitudes.
Why it’s popular#
“8% off” is instantly meaningful to non-specialists and lets you compare accuracy across products or regions on different scales — hence its ubiquity in demand forecasting and business reporting.
The pitfalls#
MAPE explodes when actuals are zero or near-zero (the denominator → 0), and it is asymmetric — over-forecasts can incur unbounded percentage error while under-forecasts are capped at 100%, biasing it toward models that under-predict. For intermittent or zero-heavy data, scaled errors like MASE are safer.
Theme: Model Evaluation & Uncertainty · All terminology
Hint
Mind map — connected ideas
Mean Squared Error (MSE) · Root Mean Squared Error (RMSE) · Relative accuracy · Forecast Error · R² (R-squared) · Regression Models
Hint
More in Model Evaluation & Uncertainty
Average Absolute Error (AAE) · Baseline Heuristics · Bootstrap · Bootstrap Confidence Intervals (CIs) · Coverage · Cramér’s V · DeLong’s Test · KS Statistic (Kolmogorov–Smirnov Statistic) · Likelihood Ratio (LR) · Mann–Whitney U Test (also called the Wilcoxon rank-sum test) · MASE (Mean Absolute Scaled Error) · Mean Absolute Error (MAE) · Mean Squared Error (MSE) · Relative accuracy
See also
Source article Adapted (context, re-expressed) in our own words from: Mean Absolute Percentage Error (MAPE) (insightful-data-lab.com).