The Department of Defense (DoD) has adopted Six Sigma as the basis for a disciplined methodology to improve its processes. To reduce variability of human processes is a challenge introduced by "Human Sigma" advocates. It focuses on adapting Six Sigma discipline to measuring and improving human competencies. DoD is one of the largest employers, with an ongoing need to measure and assess human performance effectiveness in the context of mission accomplishment. Accurately measuring performance, although labor-intensive and expensive, is most importantly, science-driven. Conserving valuable resources is at the heart of current knowledge management efforts using human performance metrics. With shrinking budgets and workforces, and the complexity of new technologies and warfighting environments, the time is ripe for instituting such an initiative. This paper illuminates efficiencies, cost-savings, and quality to be gained through developing a knowledge management system (KMS) for human performance assessment (KMS-HPA) for the military. We examine recent United States and International efforts to capture and manage knowledge about measures and their development, from such domains as air traffic control, human factors, and command and control. We examine lessons learned as they apply to enterprise level initiatives, since no such capability exists to support the evaluation of warfighter performance. As complexity of future military operations escalates, and as multinational militaries unite in common operations, we face new and unknown challenges for measuring mission success. Improvements in processes for measuring performance effectiveness should enhance future readiness.