Jan Klabbers introduced the terms science of analysis and science of design. The science of analysis uses games and simulations as research methods to test theories in various fields. Research in the science of design perspective emphasizes the design of the artifact, and testing its usability. However, in which way both communities can be of mutual benefit remains controversial. The authors discuss the potential contributions of theory-based evaluation in order to link both communities. Theory-oriented evaluation approaches are based on logic models which have the function of outlining how the simulation, its participants, and its environment interact with each other, and elicit the simulation's desired outcomes. Its primary aim is to gain evaluative knowledge from a particular gaming simulation which can then be used to improve the simulation and its implementation for practical purposes. The authors illustrate their viewpoints by discussing the theory-oriented evaluation of a business simulation game.