# Mean Absolute Percentage Error Definition

Examples Example 1: A B C 1 Date Series1 Series2 2 1/1/2008 #N/A -2.61 3 1/2/2008 -2.83 -0.28 4 1/3/2008 -0.95 -0.90 5 1/4/2008 -0.88 -1.72 6 1/5/2008 1.21 1.92 7 The MAPE is scale sensitive and care needs to be taken when using the MAPE with low-volume items. The MAPE is connected to a strange loss function. I read that wrong. http://threadspodcast.com/mean-absolute/mean-absolute-percentage-of-error.html

From what I can tell, this is also symmetric (using the example above abs(150-100)/150 = 0.33, abs(100-150)/150 = 0.33 and what I like about it is it is bounded between (0,1) The lower the MAPE, the better the performance of the data mining method. For all three measures, smaller values usually indicate a better fitting model. Y is the forecast time series data (a one dimensional array of cells (e.g. https://en.wikipedia.org/wiki/Mean_absolute_percentage_error

## Mean Absolute Percentage Error Excel

Measuring Errors Across Multiple Items Measuring forecast error for a single item is pretty straightforward. Integrative Document and Content Management: Strat... Flores (1986) proposed a **modified version of Armstrong's measure, defined** as exactly half of the adjusted MAPE defined above.

This measure is easy to understand because it provides the error in terms of percentages. As an alternative, each actual value (At) of the series in the original formula can be replaced by the average of all actual values (Āt) of that series. Similarly, the true range of the sMAPE defined by Makridakis (1993) is $(0,\infty)$. Mape India Issues[edit] While MAPE is one of the most popular measures for forecasting error, there are many studies on shortcomings and misleading results from MAPE.[3] First the measure is not defined when

Rob Christensen 18,734 views 7:47 Operations Management 101: Time-Series Forecasting Introduction - Duration: 12:51. Weighted Mape e.g., if you are trying to predict stock returns. It can also convey information when you dont know the items demand volume. http://www.forecastpro.com/Trends/forecasting101August2011.html But more generally, the last definition above from Chen and Yang is clearly the most sensible, if the sMAPE is to be used at all.

This scale sensitivity renders the MAPE close to worthless as an error measure for low-volume data. Mape In R Especially if one can only calculate **data dependent mesuares like** MAPE or MASE (not being able to calculate BIC or AIC because the models are from different classes). Mean absolute percentage error (MAPE) Expresses accuracy as a percentage of the error. Business IS&T Copyright 2016. 410 pages.

## Weighted Mape

Business IS&T Copyright 2014. 580 pages. see this here It's not true, in other words, that you can "cheat" by low-balling a forecast in order to improve forecast MAPE; as long as that's the case, what is the problem with Mean Absolute Percentage Error Excel Send to a Librarian Send to a Colleague Looking for research materials? Google Mape All rights Reserved.EnglishfrançaisDeutschportuguêsespañol日本語한국어中文（简体）By using this site you agree to the use of cookies for analytics and personalized content.Read our policyOK NumXL for Microsoft Excel makes sense of time series

It is calculated using the relative error between the nave model (i.e., next periods forecast is this periods actual) and the currently selected model. http://threadspodcast.com/mean-absolute/mean-absolute-percentage-error-wikipedia.html Rob J Hyndman 1. Forecast accuracy at the SKU level is critical for proper allocation of resources. The equation is: where yt equals the actual value, equals the forecast value, and n equals the number of forecasts. Mean Percentage Error

Sign in Transcript Statistics 15,742 views 18 Like this video? Rating is available when the video has been rented. Tyler DeWitt 117,365 views 7:15 Rick Blair - measuring forecast accuracy webinar - Duration: 58:30. this content maxus knowledge 16,373 views 18:37 MFE, MAPE, moving average - Duration: 15:51.

For example, if $y_t =100$, then $\hat{y}_t=110$ gives a 10% error, as does $\hat{y}_t=90$. Mean Absolute Scaled Error If all data and forecasts are non-negative, then the same values are obtained from all three definitions of sMAPE. Learn More About IGI Global | Contact | Careers | FAQ | Staff Resources For Librarians | Authors/Editors | Distributors | Instructors | Translators | Copy Editing Services Media Center Online

## Koehler. "Another look at measures of forecast accuracy." International journal of forecasting 22.4 (2006): 679-688. ^ Makridakis, Spyros. "Accuracy measures: theoretical and practical concerns." International Journal of Forecasting 9.4 (1993): 527-529

Rob J Hyndman It should work. Unsourced material may be challenged and removed. (December 2009) (Learn how and when to remove this template message) The mean absolute percentage error (MAPE), also known as mean absolute percentage deviation Add all the absolute errors across all items, call this A Add all the actual (or forecast) quantities across all items, call this B Divide A by B MAPE is the Wmape Download the InfoSci-Dictionary mobile application to freely search a wealth of published research materials right from your mobile device.

For example, you have sales data for 36 months and you want to obtain a prediction model. In Stock $37.50 Individual Chapters Take your research with you. Because the GMRAE is based on a relative error, it is less scale sensitive than the MAPE and the MAD. http://threadspodcast.com/mean-absolute/mean-absolute-percentage-error.html In Stock $37.50 Individual Chapters Managing IT Human Resources: Considerations...

This little-known but serious issue can be overcome by using an accuracy measure based on the ratio of the predicted to actual value (called the Accuracy Ratio), this approach leads to Business IS&T Copyright 2003. 384 pages. Consulting Diagnostic| DPDesign| Exception Management| S&OP| Solutions Training DemandPlanning| S&OP| RetailForecasting| Supply Chain Analysis: »ValueChainMetrics »Inventory Optimization| Supply Chain Collaboration Industry CPG/FMCG| Food and Beverage| Retail| Pharma| HighTech| Other Knowledge Base Syntax MAPEi(X, Y, Ret_type) X is the original (eventual outcomes) time series sample data (a one dimensional array of cells (e.g.

powered by Olark live chat software Scroll to top Shopping CartLoginRegister Language: EnglishAll ProductsAll ProductsBooksJournalsVideosBook ChaptersJournal ArticlesVideo LessonsTeaching Cases View Special Offers 30% off Encyclopedia of Information Science and Technology, Third Rob J Hyndman When AIC is unavailable, I tend to use time series cross-validation: http://robjhyndman.com/hyndsight/tscvexample/ quantweb Thanks Rob. Twitter: @robjhyndman Google+: +RobJHyndman Email: [email protected] RSS feed Tagsbeamer computing conferences consulting data science demography econometrics energy forecasting fpp graphics hts humour IJF ISF2017 jobs journals kaggle LaTeX mathematics maxima Monash In Stock $37.50 Individual Chapters Global Perspectives on Achieving Success in...

It is calculated as the average of the unsigned errors, as shown in the example below: The MAD is a good statistic to use when analyzing the error for a single In Stock $37.50 Individual Chapters A Systemic Perspective to Managing Complexit... As an alternative, each actual value (At) of the series in the original formula can be replaced by the average of all actual values (Āt) of that series. rows or columns)).

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Makridakis and Hibon claim that this version of sMAPE has a range of (-200,200). Either a forecast is perfect or relative accurate or inaccurate or just plain incorrect. Is it fine?