Real aggregated percentage error
Encyclopedia
In spectral analysis
of time series
data in statistics
, mean absolute percentage error
(MAPE) is measure of accuracy in a fitted time series value in statistics
, specifically trending
. It usually expresses accuracy as a percentage. The MAPE is a useful measure for measuring the accuracy of a single unit in a time series.
However, in practical application of time series analysis, such as in demand or economic forecasting, it is often necessary to aggregate a sum of separate but related time series. One such example is in forecasting the sales outlook for a variety of products. Though MAPE will tell the accuracy of each product, it has a major drawback in that a simple average might distort the analysis, effectively "washing out" high-accuracy series with low-accuracy series. To compensate for this shortcoming, forecast practitioners will calculate some weighted value of the individuals MAPEs. This is known as the real aggregated percentage error (RAPE) or weighted absolute percentage error (WAPE); both are common and accepted forecast-industry terms. They vary slightly in that WAPE will give a higher weight to series with higher observations (volumes, units of sale, etc.), where RAPE will use some other criterion for weighting the individual accuracy, such as margin, impact (higher regressor values), or importance to the forecaster or analyst.
Spectral analysis
Spectral analysis or Spectrum analysis may refer to:* Spectrum analysis in chemistry and physics, a method of analyzing the chemical properties of matter from bands in their visible spectrum...
of time series
Time series
In statistics, signal processing, econometrics and mathematical finance, a time series is a sequence of data points, measured typically at successive times spaced at uniform time intervals. Examples of time series are the daily closing value of the Dow Jones index or the annual flow volume of the...
data in statistics
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
, mean absolute percentage error
Mean Absolute Percentage Error
Mean absolute percentage error is measure of accuracy in a fitted time series value in statistics, specifically trending. It usually expresses accuracy as a percentage, and is defined by the formula:...
(MAPE) is measure of accuracy in a fitted time series value in statistics
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
, specifically trending
Trend estimation
Trend estimation is a statistical technique to aid interpretation of data. When a series of measurements of a process are treated as a time series, trend estimation can be used to make and justify statements about tendencies in the data...
. It usually expresses accuracy as a percentage. The MAPE is a useful measure for measuring the accuracy of a single unit in a time series.
However, in practical application of time series analysis, such as in demand or economic forecasting, it is often necessary to aggregate a sum of separate but related time series. One such example is in forecasting the sales outlook for a variety of products. Though MAPE will tell the accuracy of each product, it has a major drawback in that a simple average might distort the analysis, effectively "washing out" high-accuracy series with low-accuracy series. To compensate for this shortcoming, forecast practitioners will calculate some weighted value of the individuals MAPEs. This is known as the real aggregated percentage error (RAPE) or weighted absolute percentage error (WAPE); both are common and accepted forecast-industry terms. They vary slightly in that WAPE will give a higher weight to series with higher observations (volumes, units of sale, etc.), where RAPE will use some other criterion for weighting the individual accuracy, such as margin, impact (higher regressor values), or importance to the forecaster or analyst.
See also
- Mean absolute percentage errorMean Absolute Percentage ErrorMean absolute percentage error is measure of accuracy in a fitted time series value in statistics, specifically trending. It usually expresses accuracy as a percentage, and is defined by the formula:...
- Mean absolute errorMean absolute errorIn statistics, the mean absolute error is a quantity used to measure how close forecasts or predictions are to the eventual outcomes. The mean absolute error is given by...
- Symmetric mean absolute percentage errorSymmetric mean absolute percentage errorSymmetric mean absolute percentage error is an accuracy measure based on percentage errors. It is usually defined as follows:where At is the actual value and Ft is the forecast value....
(sMAPE)