Figure 2.

Model verification and substantiation workflow. The workflow shown is an adaption of the verification and validation processes (Figure 1) for the comparison of two executable models (i.e., a model-to-model validation test). The executable models share the same system of interest and the same mathematical model, but differ in the model implementation (e.g., by using different simulation engines). We propose the term “substantiation” instead of “validation” to indicate that this assessment activity cannot evaluate the accuracy of the model with respect to its system of interest. Modeling and simulation activities are indicated by black solid arrows, whereas assessment activities are indicated by red dashed arrows. Figure amended from Trensch et al. (2018).