Defining and validating measures for object-based high-level design

The availability of significant measures in the early phases of the softwar e development life-cycle allows for better management of the later phases, and more effective quality assessment when quality can be more easily affec ted by preventive or corrective actions. In this paper, we introduce and co mpare Various high-level design measures for object-based software systems. The measures are derived based on an experimental goal, identifying fault- prone software parts, and several experimental hypotheses arising from the development of Ada systems for Flight Dynamics Software at the NASA Goddard Space Flight Center (NASA/GSFC). Specifically, we define a set of measures far cohesion and coupling, which satisfy a previously published set of mat hematical properties that are necessary for any such measures to be valid. We then investigate the measures' relationship to fault-proneness an three large scale projects, to provide empirical support for their practical sign ificance and usefulness.