The validation of commercial system dynamics models

This paper discusses the need for formal criteria for the establishment of confidence in, or the ‘‘validation’’ of, system dynamics models constructed for fee-paying clients as opposed to for academic research purposes. The meaning of ‘‘validation’’ is first considered and the substantial differences between the consultancy and academic cases are discussed. That leads to a review of the system dynamics literature on tests of validity. Finally, there is a discussion of the process of consultancy in system dynamics. An outline of a set of formal tests is described.