A performance measurement tool known as TRACE (Tactically Relevant Assessment of Combat Events) was developed and used to assess Command/Control (C2) staff training. TRACE allows the collection of detailed process measures in an efficient, streamlined manner. Alternate versions of TRACE were developed for each of four organizational elements related to the C2 staff. The performance of teams within these elements was assessed during field-based tactical exercises driven by C2 equipment stimulators and a time ordered events list. Observers scored the performance of these teams using TRACE checklists that were either based on the timed sequence of activities in the exercise, or on tasks that were done routinely. Portable, hand-held computers automatically opened the required checklist at the required time for each observer/controller. The computers provided a substantial increase in the efficiency and accuracy of data collection. In general, performance of the C2 staff elements improved over the time period covered by the exercises. This paper will: (1) describe the training environment used for this measurement project, (2) discuss the development of computer-based, hand-held performance measurement tools for use in field-based exercises to assess C2 staff performance, and (3) present selected data summaries of C2 performance as captured by the measurement tools.