Table of Contents
What is Diebold-Mariano test?
The Diebold-Mariano test compares the forecast accuracy of two forecast methods. dm.test( e1, e2, alternative = c(“two.sided”, “less”, “greater”), h = 1, power = 2 )
What is Mase in forecasting?
In statistics, the mean absolute scaled error (MASE) is a measure of the accuracy of forecasts. It is the mean absolute error of the forecast values, divided by the mean absolute error of the in-sample one-step naive forecast. It was proposed in 2005 by statistician Rob J.
Which forecasting model is best?
Top Four Types of Forecasting Methods
| Technique | Use |
|---|---|
| 1. Straight line | Constant growth rate |
| 2. Moving average | Repeated forecasts |
| 3. Simple linear regression | Compare one independent with one dependent variable |
| 4. Multiple linear regression | Compare more than one independent variable with one dependent variable |
How is Mase measured?
How MASE is calculated is as follows.
- Absolute value of (Subtract the forecast from the actuals)
- Take the average the absolute error of the product location combinations or the MAE.
- Divide the error by the MAE.
How do you read MAPE?
The mean absolute percent error (MAPE) expresses accuracy as a percentage of the error. Because the MAPE is a percentage, it can be easier to understand than the other accuracy measure statistics. For example, if the MAPE is 5, on average, the forecast is off by 5%.
Is low MAPE good or bad?
Since MAPE is a measure of error, high numbers are bad and low numbers are good. For reporting purposes, some companies will translate this to accuracy numbers by subtracting the MAPE from 100. You can think of that as the mean absolute percent accuracy (MAPA; however this is not an industry recognized acronym).
Is it possible to have a MAPE higher than 100?
Expressed as a percentage, which is scale-independent and can be used for comparing forecasts on different scales. We should remember though that the values of MAPE may exceed 100%.
What is Mase metric?
Mean Absolute Scaled Error (MASE) is a scale-free error metric that gives each error as a ratio compared to a baseline’s average error.
How do you calculate a forecast?
The formula is: previous month’s sales x velocity = additional sales; and then: additional sales + previous month’s rate = forecasted sales for next month.
What is acceptable MAPE?
A MAPE less than 5% is considered as an indication that the forecast is acceptably accurate. A MAPE greater than 10% but less than 25% indicates low, but acceptable accuracy and MAPE greater than 25% very low accuracy, so low that the forecast is not acceptable in terms of its accuracy.
What is an acceptable MAPE value?
How do you calculate Mase?
The Diebold-Mariano test compares the forecast accuracy of two forecast methods. dm.test(e1, e2, alternative = c (“two.sided”, “less”, “greater”), h = 1, power = 2)
Does the Diebold-Mariano test reject the null hypothesis?
Actually, the Diebold-Mariano test tends to reject the null hypothesis too often for small samples. A better test is the Harvey, Leybourne and Newbold (HLN) test, which is based on the following:
How to calculate standard errors and Diebold-Mariano statistics?
The standard errors (column J) and Diebold-Mariano statistics (column K) can next be calculated. E.g. cell J4 contains the formula =SQRT (J25/E23), cell J5 contains =SQRT ( (J$25+2*SUMPRODUCT (I$4:I4))/E$23) (and similarly for the other cells in column J) and cell K4 contains the formula =G$25/J4.