RODNEY D. STEWART is President of Mobile Data Services, and senior staff consultant for Science Applications International Corporation and Computer Systems Technology. He has served as project engineer and project manager with the National Aeronautics and Space Administration, and as manager of the cost analysis office in the Systems Analysis and Integration Laboratory of NASA's George C. Marshall Space Flight Center in Huntsville, Alabama. He is a past national president and past national policy director of the National Estimating Society, and a certified cost estimator/analyst.