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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 This installment of Forecasting 101 surveys common error measurement statistics, examines the pros and cons of each and discusses their suitability under a variety of circumstances. Learn more You're viewing YouTube in Greek. Notice that because "Actual" is in the denominator of the equation, the MAPE is undefined when Actual demand is zero. check over here

The mean absolute percentage error (MAPE) is defined as follows:

Where: is the actual observations time series is the estimated or forecasted time series is the number of non-missing data points 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 PivotTableGuy 30.765 προβολές 7:01 Introduction to Mean Absolute Deviation - Διάρκεια: 7:47. The symmetrical mean absolute percentage error (SMAPE) is defined as follows: The SMAPE is easier to work with than MAPE, as it has a lower bound of 0% and an upperSo we constrain Accuracy to be between 0 and 100%. When MAPE is used to compare the accuracy of prediction methods it is biased in that it will systematically select a method whose forecasts are too low. Were students "forced to recite 'Allah is the only God'" in Tennessee public schools? This alternative is still being used for measuring the performance of models that forecast spot electricity prices.[2] Note that this is the same as dividing the sum of absolute differences by

The MAPE is often expressed as a percentage, that is, $0.057$ would be reported as $5.7\%$. Does flooring the throttle while traveling at lower speeds increase fuel consumption? Inaccurate demand forecasts typically would result in supply imbalances when it comes to meeting customer demand. How To Calculate Forecast Error In Excel Ed Dansereau 15.324 προβολές 1:42 How To...

IntroToOM 67.208 προβολές 3:45 Forecast Accuracy Mean Average Percentage Error (MAPE) - Διάρκεια: 1:42. Google Mape However, there is a **lot of confusion** between Academic Statisticians and corporate Supply Chain Planners in interpreting this metric. Excel Analytics 3.776 προβολές 5:30 Forecasting - Measurement of error (MAD and MAPE) - Example 2 - Διάρκεια: 18:37.

You can change this preference below. Κλείσιμο Ναι, θέλω να τη κρατήσω Αναίρεση Κλείσιμο Αυτό το βίντεο δεν είναι διαθέσιμο. Ουρά παρακολούθησηςΟυράΟυρά παρακολούθησηςΟυρά Κατάργηση όλωνΑποσύνδεση Φόρτωση... Ουρά παρακολούθησης Ουρά __count__/__total__ MFE,

The MAD The MAD (Mean Absolute Deviation) measures the size of the error in units. Mean Absolute Scaled Error As stated previously, percentage errors cannot be calculated when the actual equals zero and can take on extreme values when dealing with low-volume data. The MAPE and MAD are the most commonly used error measurement statistics, however, both can be misleading under certain circumstances. 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

Powered by vBulletin Version 4.2.3 Copyright © 2016 vBulletin Solutions, Inc. my company For those not familiar with this measure, basically I need a function that will calculate the absolute percentage difference between the values for two variables and return the average or sum Mean Absolute Percentage Error Formula more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed Weighted Mape So $|w_1-m_1|$ measures the "error" made in weighing the first person.

Either a forecast is perfect or relative accurate or inaccurate or just plain incorrect. http://edvinfo.com/mean-absolute/mean-absolute-deviation-formula.html Measuring Errors Across Multiple Items Measuring forecast error for a single item is pretty straightforward. 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 romriodemarco 67.317 προβολές 15:22 Forecasting with Seasonality - Διάρκεια: 16:37. Mean Percentage Error

The MAD/Mean ratio is an alternative to the MAPE that is better suited to intermittent and low-volume data. Clyde Lettsome 3.088 προβολές 10:28 Weighted Moving Average - Διάρκεια: 5:51. By using this site, you agree to the Terms of Use and Privacy Policy. http://edvinfo.com/mean-absolute/mean-absolute-percentage-of-error.html Furthermore, when the Actual value is not zero, but quite small, the MAPE will often take on extreme values.

A potential problem with this approach is that the lower-volume items (which will usually have higher MAPEs) can dominate the statistic. Mape In R How can I call the hiring manager when I don't have his number? 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

Please help improve this article by adding citations to reliable sources. The statistic is calculated exactly as the name suggests--it is simply the MAD divided by the Mean. Forecast Using Exponential Smoothing in Excel 2013 - Διάρκεια: 6:22. Forecast Accuracy Definition In order to avoid this problem, other measures have been defined, for example the SMAPE (symmetrical MAPE), weighted absolute percentage error (WAPE), real aggregated percentage error, and relative measure of accuracy

Excel - Tips and Solutions for Excel Privacy Statement Terms of Service Top All times are GMT -4. And $\dfrac{|w_1-m_1}{w_1}$ measures the relative error made in weighing. Why doesn't compiler report missing semicolon? have a peek at these guys Calculating error measurement statistics across multiple items can be quite problematic.

statistics share|cite|improve this question asked Nov 20 '12 at 3:42 Raynos 71341538 add a comment| 1 Answer 1 active oldest votes up vote 1 down vote accepted Suppose that you weigh Y is the forecast time series data (a one dimensional array of cells (e.g. The GMRAE (Geometric Mean Relative Absolute Error) is used to measure out-of-sample forecast performance. IntroToOM 116.704 προβολές 3:59 Mean Absolute Deviation (MAD) - Διάρκεια: 3:22.

Analytics University 44.813 προβολές 53:14 MFE, MAPE, moving average - Διάρκεια: 15:51. For a plain MAPE calculation, in the event that an observation value (i.e. ) is equal to zero, the MAPE function skips that data point. Hot Network Questions In what way was "Roosevelt the biggest slave trader in recorded history"? Please help improve this article by adding citations to reliable sources.

Not familiar with the strange formulas in this question either...Hopefully someone knows something about this. GMRAE. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. Syntax MAPEi(X, Y, Ret_type) X is the original (eventual outcomes) time series sample data (a one dimensional array of cells (e.g.

Not the answer you're looking for? If actual quantity is identical to Forecast => 100% Accuracy Error > 100% => 0% Accuracy More Rigorously, Accuracy = maximum of (1 - Error, 0) Sku A Sku B Sku Let $w_1,w_2,\dots,w_9$ be the actual weights of the people, say measured using a high precision scale, and let $m_1,m_2,\dots,m_9$ be their measured weights using our low quality scale. archived preprint ^ Jorrit Vander Mynsbrugge (2010). "Bidding Strategies Using Price Based Unit Commitment in a Deregulated Power Market", K.U.Leuven ^ Hyndman, Rob J., and Anne B.