Today the great majority of target acquisition models within the Department of Defense (DoD) originate from two primary sources of empirical human observer data: the Blackwell-Tiffany visual perception experiments begun in World War II and the Army Night Vision Electrooptic Sensors Directorate (NVESD) field test trials with military observers. An extensive sensitivity analysis that compares the performance of several DoD acquisition models derived from these two extensive sets of data was carried out. A comprehensive analysis of each method and a detailed comparison of these different methodologies shows that they are in remarkably good agreement throughout their ranges of applicability. The authors show when the various modeling methodologies are applicable for a variety of military sensor and countermeasure scenarios.