Operational Analysis (OA) is a management science discipline which employs a range of scientific methods and analytical techniques to understand complex problems and provide a rigorous evidence base for improved decision making. The OA SL provides full-spectrum operational analysis support to planners and decision makers within NATO and the nations. This includes supporting the NATO Defence Planning Process (NDPP) and nations' defence planners, Operations Assessment for current and future Alliance missions, supporting functional / Peace Establishment analysis and reviews, and identifying Information and Knowledge Management (IKM) needs and recommendations for enterprise change. Analytical support is also provided to other Service Lines within the Agency, for instance providing operational expertise to support architecture development as well as the capture and validation of users' requirements. Although one of the smaller entities within the Agency, the OA SL already has a strong track record of delivering successful on-time solutions to complex, cross-functional problems. With increasing focus on value for money in an era of Smart Defence, the need for rigorous, justifiable and accountable decision making only looks likely to increase.