Model Initialization 

Model initialization is the process of determining the necessary model parameters¾such as the basic value, the trend value, and the seasonal indices ¾for the selected forecast model. Initialization takes place each time a planning time series is forecasted.

The following table shows you which model parameters are necessary for each forecast model.

Model

Model parameters

Constant model

Basic value

Trend model

Basic value, trend value

Seasonal model

Basic value, seasonal indices

Seasonal trend model

Basic value, trend value, seasonal indices

 

As a general rule, the forecast model is initialized automatically. In order to do this, the system requires a certain number of historical values. This number depends on the forecast model, as shown in the following table.

Model

No. of historical values

Constant model

1

Trend model

3

Seasonal model

1 season

Seasonal trend model

1 season + 3

2nd-order exp. smoothing

3

Moving average

1

Weighted moving average

1

 

The system calculates the basic value on the basis of the average and the trend using the results of the regression analysis. The seasonal indices are given by the actual historical value divided by the basic value adjusted for the trend value.

These calculation methods are used for the constant, trend, seasonal, and seasonal trend models, depending on which parameters are to be determined.

A regression analysis is carried out for the second-order exponential smoothing model.

For the moving average and weighted moving average models, the system calculates an average value.