Measuring productivity associated with software products and their development historically has been difficult. Reliable operational measurements are needed to analyze a software product and its development process. To improve both the quality of the software product and the productivity of its development process, the input to and output from the development process must be measured accurately and appropriate productivity factors must be identified and understood. To measure productivity accurately, the software development process must be well understood and the measurements should be closely linked to the development process and the development environment. This paper describes the software productivity measurement metrics, the important productivity factors, and some applications of the software productivity data for the 5ESS® switch developed for the United States market. The measurement of production rate and the study of productivity factors have established a solid foundation for the pursuit of productivity and quality improvement within the 5ESS switch development community.