Organizations, including the military, are producing an exponentially growing amount of data due to the rising use of technology including multimedia, social media, smartphones, and data sensors, not to mention conventional methods of communication such as email, chat, and phone. Strategic use of so-called big data is one way for the United States military to maintain a competitive advantage. Although the amount of potential data available is vast, there are many challenges to capturing the full potential of big data-driven strategies, including storage, curation, visualization, and analysis. Further, most approaches to utilizing big data make the mistake of relying solely on a data-driven approach, largely ignoring theory, science, and contextual expertise (Graham, 2012). The purpose of this paper is twofold: first, to present the perceived benefits of utilizing big data to monitor and measure individual and team performance in command and control environments; and second, to describe a new method of developing organizational performance measures which utilize big data but are also rooted in an understanding of theory and context. The Rational Approach to Developing Systems-based Measures (RADSM) is a series of six steps which consider theory, data availability, and a range of multi-disciplinary data analysis methods combined to develop measures of a construct of interest in a top-down and bottom-up approach. The RADSM process emerged from several years of research focused on developing unobtrusive performance measures for large military organizations. The underlying logic of RADSM is that as organizational members interact with one another, their actions - such as communicating with one another, making collaborative decisions, and executing their individual position-related duties - leave behind "trace data" that provide insight into individual and collective states. The authors of this paper have found RADSM to be a flexible approach by which to thoughtfully organize the mining of big data for performance assessment.