Before you run a forecast, you must specify which model the system should use to calculate the forecast values. Your selection will depend on your knowledge of the data pattern to-date.

Historical values are available and you can make conclusions from these regarding the most appropriate forecast model.

Model selection alternatives are as follows:

• manual model selection
  You determine the forecast according to your preferred model. This is suitable when you have a clear idea of the future development of the key figures although this development will have a different pattern to their development in the past. In this case, the future data cannot be derived mathematically from the historical data and you must let the system know how to proceed.

• automatic model selection
  The pattern to-date enables you to determine the presence of seasonality or another trend and, therefore, you run a test to find the closest development pattern.

The following graphic shows the different approaches of automatic model selection and manual determination of a forecast model: