Abstract: All models are abstractions of the real world. Determining the appropriate level of abstraction is a balancing of the complexity of the system being modeled, the available data resolution provided by data sources and subject matter experts, the needs of decision makers, and the limitations of the computational and developmental resources. Results from algorithmically linear, physical, closed-system simulations can often be improved by using higher-resolution inputs and by modeling lower-order phenomena. It is not as obvious; however, that ever-increasing resolution will necessarily improve the results from modeling complex systems. Two military course-of-action (COA) development case studies are examined to determine what level of model resolution is sufficient to provide significant insight into COA development. We examine the appropriate level of fidelity for modeling force structures and behaviors as well as the appropriate level of detail for modeling the terrain and physical environment. Methods for evaluating and comparing the results of varying model resolutions are presented.