This presentation provides a heuristic for developing mission-based metrics for evaluating weapons systems in an operational environment. The process can be applied across a range of weapons systems. The scope of the metrics is determined by looking at end-to-end mission accomplishment through the lens of the particular weapons system or upgrade to be tested. For each system, we look at the typical operator and to what unit the operator is assigned, or to whom that unit is providing support. The distinction is important as operators are given tasks while units are tasked to conduct missions.