The Eye of the Beholder: A Case Example of Changing Clients' Perspectives Through Involvement in the Model Validation Process

Validation is an important topic in the system dynamics field. A large body of knowledge addresses validation tests and procedures. However, the use of validation in practice and its results are scarcely reported. This is surprising as some authors assume that in order to build confidence in a model, it is crucial to at least communicate the validation process and its results. In this paper, we described a validation process in direct interaction with clients. We describe the tests and procedures we employed to iteratively build and validate a simulation model with the National Health Care Institute (The Netherlands) in a group model‐building setting. The involvement challenged the clients' opinions and in some cases led to changes in their mental models.