The usability of graphical modeling languages has not been explicitly considered in past research. Most usability evaluation surveys are mainly focusing on applications, websites, software and technical products. Usability has not been focused on within the development of current graphical languages for conceptual modeling. Consequently, the impact of graphical modeling languages on users as well as the output resulting from their application is not clear. Dr. Christian Schalles focuses on an empirical usability evaluation of graphical modeling languages in business process and software modeling.