Forecasting System Decisions:

Management should make decisions with regard to the data and the method(s) that will be used to prepare a forecast. The data can be available in the form needed or may need adjustment or aggregation. If demand data is available for the past several years, decision ought to be made as to "how far back to go."

The choice of method to be utilized for the preparation of forecast depends on the quantity and quality of data available, the time needed, and the expertise that is available or can be secured.