You use this program to asses the accuracy of previous forecasts.
The program calculates the accuracy scores (Standard deviation, Mean Absolute deviation and average hits), which are used as inputs to either the Poisson or Normal algorithm in the IO Stock Levels Modeling program.
| Field | Description |
|---|---|
| Functions | |
| Stock Code Options | Select this to use the Options Maintenance program to maintain the forecasting options to use. |
| Policies | Select this to use the IO Policies program to maintain policy options to generate the suggested minimum/maximum levels. |
| Manual Forecasting | Select this to use the Manual Forecasting program to make changes to the forecasts. |
| Demand History | Select this to use the Demand History Maintenance program to adjust the sales history (i.e. the demand history) for the forecast. |
| View | |
| Quantities | Select this to display quantities in the Details listview. |
| Sales Values | Select this to display sales values in the Details listview. |
| Cost Values | Select this to display cost values in the Details listview. |
| Selection | |
| Manual | Select this to indicate individual stock items for which you want to compute the forecast accuracy. The Warehouse and Stock code fields are enabled when you select this option. |
| Batch | Select this to use the IO Selections program to indicate a selection set or range of stock codes for which you want to compute the forecast accuracy. |
| Warehouse | This indicates the warehouse for which the forecast
accuracy is being computed. You can only enter the warehouse
if you selected Manual at the
Selection menu. If you are running the program in Batch selection mode, then you use the Prev and Next options to navigate to the required warehouse. |
| Stock code | This indicates the stock code for which the forecast
accuracy is being computed. You can only enter the stock code
if you selected Manual at the
Selection menu. If you are running the program in Batch selection mode, then you use the Prev and Next options to navigate to the required stock code. |
| Change Rev/Rel | Select this to enter a different revision/release if the stock item is ECC controlled. |
| Calculate | Select this to re-calculate the forecast accuracy after changes have been made in the Information pane. The results are displayed in the Details listview. |
When you make any changes to options in this pane, you use the Calculate function to display the results of those changes in the Details listview. If you are satisfied with the results displayed in the Details listview, you can manually make the same changes to the Modeling Options in the IO Stock Levels Modeling program.
| Field | Description | ||||
|---|---|---|---|---|---|
| Options | Apart from the Run date (which defaults to the current system date), the selections in this section default to the modeling selections made in the Factory Scheduling Setup program. | ||||
| Run date | Indicate the date from which the forecast accuracy must be run. | ||||
| Months to compare | Select the default number of months to compare for
forecast accuracy (1-12).
|
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| Comparison type | |||||
| Period on period | Select this to calculate forecast accuracy by comparing each period's sales and forecasts to get the absolute deviation. | ||||
| Moving average | Select this to calculate forecast accuracy by averaging the sales and forecasts over a number of periods. | ||||
| Moving average months | If you set the comparison type to Moving
average, then you need to enter the number of
months to use for the moving average calculation of sales
history. As with Months to compare, this is converted to periods depending on the calendar in use. |
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| Forecast to use | |||||
| Last | Select this to use the last forecast taken for the period to compare against sales for each period. | ||||
| Last outside lead time | Select this to use the last forecast taken for the
period outside of the lead time and dock-to-stock (i.e.
planning time fence) to compare against sales for each
period.
|
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| Average | Select this to use the average calculated for snapshots taken for this period to compare against sales for each period. | ||||
| Average outside lead | This uses the average, but only uses snapshots taken outside of the lead time. | ||||
| Snapshot months | If the forecast to use is Average
or Average outside lead, then the number
of months entered here determines how many forecast snapshots
to use when calculating the average. For example: You have a weekly calendar and, historically, you created a live forecast for an item for each week. If you select 2 months here then the snapshot quantities are added for the period taken over the last 8 weeks and averaged out for comparison. |
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| Calendar to use | Indicate the IO forecast calendar to use for the forecast accuracy. | ||||
![[Note]](images/note.png)
This displays a graphical representation of the sales versus the selected forecast for the warehouse/stock code combination.
This pane displays the static stock code information from the Inventory Master table for the stock code.
This displays the forecast's accuracy scores. These are the same scores used as an input to either the Poison or Normal algorithm in modeling (see IO Stock Levels Modeling - Modeling options - Calculated information). These algorithms are used to generate the min/max levels in modeling.
These values can vary widely depending on the number of Moving average months you select and the actual accuracy of your forecasts over those months.
The forecast accuracy results are displayed in this listview when you select the Calculate option. The forecast values are compared to the actual sales values.
The values displayed are either the quantities, sales values or cost values depending on your selection in the View menu.
Additional columns can be added to the listview by right clicking in any column heading and selecting the Field Chooser option.
| Column | Description |
|---|---|
| Hits | This indicates the actual number of sales for the selected period. |
| Absolute error | This is the difference between the Forecast value and the Sales value expressed as a positive value. |
| Status | This indicates whether you over forecast (forecast is more than sales) or under forecast (forecast is less than sales). |
| CFE |
This is the cumulative forecast error. This measure represents the difference between the forecast and the actual sale(s) for the period under review, displayed cumulatively. A positive number indicates a forecast that is too high for a period and a negative number indicates a forecast which is too low for a period. |
| MAD |
This is the calculated mean absolute deviation. The mean absolute deviation (MAD) is the average absolute deviation from the mean (i.e. the average error, ignoring the sign of the error). |
| MSD |
This is the calculated mean square deviation. The sum of the squared forecast errors for each observation divided by the number of observations. It is an alternative to the Mean Absolute Deviation except that, because the errors are squared, more weight is placed on larger errors. |
| MAPE |
This is the calculated mean absolute percentage error. This is calculated as the average of the sum of all the absolute percentage errors for the data set. The absolute values of the percentages are summed and the average is computed. The difference between actual value and the forecast value is divided by the actual value. The absolute value of this calculation is summed for every forecast point in time and divided again by the number of fitted points. |
| Tracking signal |
This is calculated as the algebraic sum of forecast errors divided by the Mean Absolute Deviation. It indicates whether the forecast average is keeping pace with any genuine upward or downward changes in demand. |
| Error % | This is calculated as: (Absolute error / Forecast) * 100 |
| Accuracy % | This is calculated as: (100 - Error %) |