Step 3: Choosing the relevant forecasting method From step 2                  NO        NO YES 6.1.1 Step 5: Consistency check Figure 6.1(b). Decision tree showing the 5-step procedure for forecasting product systems. Figure continued from previous page. Go to step Go to step Go to step Go to step Long (5-25 Short- term Long (5-25 Short- term Less predictable or complex Specific processes, with predictable or controlled What is the complexity of the item to be forecasted? What is the time horizon of the forecast? What is the time horizon of the forecast? Step 4e:   Use scenario methods Step 4d:   Consider the use of exploratory and normative methods Step 4b:   Use modelling Step 4a:   Use extrapolation Step 4c: Use participatory methods in combination with modelling (step 4b) Does the decision- maker control the process?