Where Have All the Equations Gone? the Forgotten Algebra of Qualitative Structural Modelling

Qualitative structural modelling (QSM) techniques have assisted decision makers with the cognitive burden of structuring and interpreting complex problematic situations. Indeed, QSM pioneered the application of graph-theoretical principles and human-computer interaction. Specific approaches include ISM (Interpretive Structural Modelling); DEMATEL (DEcision MAking Trial and Evaluation Laboratory project); and MICMAC (Matrice d’Impacts Croisés-Multiplication Appliquée à un Classement). The extant QSM research seldom advances or critically assesses these techniques. Instead, ‘template’-style research prevails across a rising number of applications. We challenge this research methodology practice by investigating procedural and algebraic aspects in QSM that are now taken as self-evident, and emphasising the extent to which individual techniques overlap or differ analytically. Results highlight the following: 1) Previously unnoticed computational similarities between techniques currently regarded as mutually exclusive; 2) Incongruences between techniques that are often applied jointly, as some techniques are often stripped of their algebraic contents; 3) Potential pitfalls in those research ‘templates’ that dispense with most algebraic and algorithmic aspects of QSM. Findings provide a unified analytical perspective on QSM, overcoming research silos centred on individual techniques. Future work should address the use of digital technologies for human-computer interaction, a prominent aspect in early QSM research now surprisingly underplayed