Many system dynamics modelers consider the process of model-building more important than the model itself. Model-building is supposed to generate considerable learning about a policy problem. Not only at the individual level but also at the organizational level. From the point of view of empirical evaluation research the question is how the occurrence of organizational learning as a consequence of a model-building process might be established. In this paper we will explore some of the key issues and difficulties involved in establishing organizational learning from model-building empirically.