Flexible Interpretive Structural Modeling (FISM) is an extended and improved version of Warfield's ISM. The algorithm of FISM is based on the Partially Filled Reachability Matrix (PR matrix) model. The PR-matrix model is an extension of a Reachability Matrix (R-matrix) model and has great utility in all phases of ISM. While, or after an Interpretive Structural Model is developed, the stakeholders may want to make amends. The procedures for "editing" an ISM or FISM structural model with the aid of a computer are called Correction Procedures. Correction procedures are the key to FISM.
Flexible interpretive structural modeling (FISM) is an extended and improved version of the interpretive structural modeling developed by J.N. Warfield (1974). The computer algorithm of FISM is based on the partially filled reachability matrix (PR matrix) model, an extension of the reachability matrix (R matrix) model that has great utility in all phases of ISM. While an FISM structural model is being developed, or after it has been developed, the developer may want to make changes (corrections) in it. Several types of corrections for FISM are defined: change of one or more entries from zero to one; change of one or more entries from one to zero; deletion of one or more elements and their connections; and addition of one or more elements and their connections. Four tuned-up correction procedures are proposed to provide effective and consistent corrections. The correction procedures, along with the implication procedures for a PR-matrix, give a complete set of procedures for implementing FISM.< >