A Dynamic Pattern-oriented Test for Model Validation1

Structure validation means establishing that the relationships used in a model are an adequate representation of the real relationships and it can be done in two ways: direct structure testing and indirect structure (or structure-oriented behavior) testing. Direct structure tests assess the validity of the model structure, by direct comparison with knowledge about real system structure. This involves evaluating each relationship in the model against available knowledge about real system. These tests are qualitative in nature; no simulation is involved. Structure-oriented behavior tests on the other hand assess the validity of the structure indirectly, by applying certain behavior tests on model-generated behavior patterns. For example, extreme-condition (indirect) test involves assigning extreme values to selected parameters and comparing the model-generated behavior to the “anticipated ” (or observed) behavior of the real system under the same extreme condition. These are “strong ” behavior tests that can provide (indirect) information on potential structural flaws. In a typical structure-oriented behavior test, the modeler makes a claim of the form: “if the system operated under condition C, then the behavior B would result. ” The model i