Robustness Analysis

Robustness Analysis is a method for evaluating initial decision commitments under conditions of uncertainty, where subsequent decisions will be implemented over time. The robustness of an initial decision is an operational measure of the flexibility which that commitment will leave for useful future decision choice.

The definition of the robustness of an initial commitment is:

the number of acceptable options at the planning horizon that are compatible with that commitment, as a ratio of the total number of acceptable options.

In more formal notation, if

• S is the set of all options at the planning horizon with acceptable performance;

• S _i is the subset of S that is compatible with initial commitment d _i ;

• and n (.) denotes the number of elements in a set

• then the robustness of commitment d _i is given by

$$ {r}\left( {{{{d}}_{{i}}}} \right) = {n}({\underset{\raise-0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{S}}_{{i}})/{n}({\underset{\raise-0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{S}}) $$