Verifying Influence Diagrams using Dimensional Analysis

Developing a valid model is of primary importance. Various verification and validation procedures are used to establish confidence in the model output. To establish confidence that a model produces right behaviour for right reasons it is essential to ensure that the structure of model represents real world system. Amongst the verification procedures employed, dimensional analysis is used to verify the syntactical correctness of the equation. Despite of its significance, dimensional analysis is one of the less prioritised procedures used during model building process. Therefore lack of dimensional consistency raises serious doubts about the validity of model behaviour. The aim of this paper is to summarise various problems and difficulties identified in System Dynamics (SD) modelling process and to suggest an alternative approach. Firstly, this paper discusses various problems faced by beginners, which can lead to errors in SD models. Secondly, discusses alternative approaches suggested by researchers in SD. Thirdly this papers presents an approach to generate mathematical model from Influence Diagrams. There are two principle benefits this approach can offer: A software tool based on this approach, and improve SD modelling experience, especially of those modellers who have limited mathematical experience so as to gain benefits of quantitative SD modelling.