Interpretative Structural Modeling / Interpretive Structural Modeling (ISM) is a general purpose analysis and decision support technique. It was invented by John N. Warfield. It provides a structured method for dealing with complex situations. It generates a visual map of the situation (or problem) that is used to obtain new insights, and construct new approaches to the problem at hand. ISM incorporates pair-wise comparison, Transitive Logic and Concept Synthesis to construct a visual map of the situation.
Source : http://www.futureworlds.eu/wiki/Interpretative_Structural_Modeling
Available for free Interpretive / Interpretative Structural Modeling (ISM) software