By using the results of the deterministic sensitivity analysis, we can
usually manage to discuss and eliminate the politically important nodes from
consideration. Indeed, this may be one of the important insights from the
analysis. If necessary, chance nodes with effects common to all alternatives
can be combined into one or two nodes whose branches represent scenarios
(combinations of events). If there are still too many nodes, we must be creative
in combining variables, restructuring the tree, and using further sensitivity
analysis to narrow down the number of important uncertainties even more.
In cases of real necessity, we may have to run a separate tree for each
alternative. If we do this, we will have to do some calculations by hand to
reorder the tree (i.e., to obtain value of information), but we can still have
software do most of the work for us.