The Army Research Institute for the Behavioral and Social Sciences (ARI) is developing a data base on the relationship between training simulator characteristics - in particular fidelity - and training effectiveness. In order to guide and organize the collection of empirical data for the data base, a two factor definition of simulator fidelity was chosen. The definition was limited to physical and functional similarity to the actual equipment. Several research efforts, using this definition, are currently being conducted or have just reached completion. This paper presents the results, to date, of completed research efforts, the anticipated results of ongoing efforts, and plans for future efforts. The goal of these efforts is to produce a data base which may serve as the foundation for the development of systematic guidance to support the specification of training device characteristics.