Defining cost/schedule performance indices and their ranges for design projects

Cost/schedule performance indices (C/SPIs) can indicate project performance, but they need to be operationally defined to be more adopted in practice. This paper defines C/SPIs and their values for design projects. From observing design operations, the C/SPIs were defined at project and milestone levels, and their characteristics were identified. The value ranges, representing different degrees of performance, were determined from related research and tested by real data. The results show that the values and scores derived from the defined ranges effectively differentiate performance, which means the C/SPIs and ranges are well defined. The two-level C/SPIs and value ranges can enhance the application of the earned value concept and evaluate design project performance more systematically and accurately.