Validation in soft OR, Hard OR and system dynamics: a critical comparison and contribution to the debate

Abstract

This paper deals with the validation ideas of three fields, namely hard OR, soft OR, and system dynamics. Validation is an important, yet a very controversial, issue on model based fields. Even though everyone seems to agree that the validation of models must be assessed, the viewpoints on what validation is and how it should be established differ widely. The purpose of this paper is to (a) describe the similarities and differences (both within and between) the three fields (b) to provide explanations for the differences, in order to (c) create mutual awareness and understanding, and (d) to increase our understanding of the issues surrounding validation. We will first start with the validation opinions of the three fields and then describe and explain the differences in these opinions and their reasons