Model simplification and validation with indirect structure validity tests

Model simplification distils essential model structures that cause selected problems and increases the quality and understanding of models. It can also be a step towards building theory-like structures and general representations of case-specific problems in various application domains. In this paper, simplification of a large system dynamics model and validation of the simplified version are illustrated. The original model represents agricultural and environmental problems of irrigation development in southeast Turkey and consists of 14 model sectors and 110 stock variables. Its simplified version with a narrow model boundary and higher level of aggregation is a general representation of its selected dynamics and consists of four model sectors and 17 stock variables only. Analysis of reference behaviours, indirect structural validity tests (structure-oriented behaviour tests) and scenario runs reveal the simplified model as a valid and useful simplification of the original one. Copyright © 2006 John Wiley & Sons, Ltd. Syst. Dyn. Rev. 22, 241–262, (2006)

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