This option may be necessary when there is a great deal of variability that you need to include in your model, but it is full of potential traps.
In VS RS US - 1 model, an attempt is made to model the total number of outbreaks. The Area and Disease (Variability components) are simulated by randomly looking up in the tables for both. The model result looks like this:
The links to the VS RS US - 1 software specific models are provided here:
The model is simple (which is always a relief), but there is an error: we have simulated areas and diseases as if they are random variables when in fact areas 1 to 4 and disease A to D are permanently present. Total outbreaks are also calculated incorrectly in the second model. VC RS US - 2 model makes a similar mistake because it assumes that the information for Diseases can be collated, as can the information for Areas. Thus, a more feasible alternative is to implement a VC/RS/UL second order model.
The links to the VC RS US - 2 software specific models are provided here:
