Forecast Parameters: Independent of the Forecast Model
You can/must maintain the following parameters independent of the method you use for model selection and which model you choose.
The period indicator determines the time interval the system is to use to store consumption or forecast values. You can define the period indicator when maintaining the MRP parameters as well as when maintaining the forecast parameters.
Fiscal year variant
You must maintain the fiscal year variant if you want a flexible period length for the material equal to that of the accounting period.
You specify how many historical values the system should take into account for the forecast by filling in this field. The default value in this case is the maximum number possible (60). If fewer values are available, then they are used for initialization.
You specify the number of periods the system is to use for model initialization here. If the number of historical values is greater than the number of initialization periods, then the system will carry out an ex-post forecast for those periods which were not used for initialization. The number of periods that the system requires for initialization depends on the forecast model.
Via the number of forecast periods, you specify for how many periods the system determines forecast values.
Via the number of fixed periods, you determine how many periods are fixed in the future and are no longer automatically changed by the next forecast run.
This field activates re-initialization during the forecast. This is necessary for the first forecast and also when structural changes (that is, if the forecast model which has been used until now has lost its validity) appear in the time series.
Model initialization can either be carried out automatically (X) or manually (M). In the case of manual initialization (which should be the exception), you must determine the model parameters manually. To do this, select Details ® Forecast details ® Model parameters. Depending on the forecast model, you can manually maintain such parameters as the basic value and the trend in the pop-up window. If you do not set these parameters here, you will be requested to set them during the forecast. No historical data has to be stored in the system in order to carry out manual initialization.
During the forecast calculation, the system compares the tracking limit with the quotient of the error total and the mean absolute deviation (MAD). This quotient is known as the tracking signal. If the value calculated by the system lies below that of the tracking limit, then the forecast remains valid. If not, the system generates an exception message which indicates that a structural interruption has taken place. This means that the forecast model should be revised and possibly re-initialized.
Causes the system to reset the forecast model automatically if the tracking limit is exceeded. Furthermore, the system carries out a new model selection during the next forecast.
If you fill in this field, historical values and forecast values are weighted with the appropriate period factors which you determined via customizing.
Reference material for consumption
If you define a reference material, the system accesses the historical data of the reference material up to the specified validity date. This makes sense, if no historical data exists yet for the specified material.
Reference plant for consumption
If you enter a reference material for consumption, you must also define a reference plant where the historical data to be used comes from.
During the forecast, the system accesses the historical data of the reference material up to the specified validity date. From this date, it uses the material’s own historical data.
By entering a multiplier, you can define that only a certain percentage of the consumption quantity of the reference material is used in the forecast.