Using Growth Models to Improve Accuracy of Estimates at Completion for over Target Baseline Contracts

Abstract

Abstract This study demonstrates the utility of using nonlinear growth modeling as an alternative to using the cost performance index (CPI), the schedule cost index (SCI), or the composite index methods for calculating estimates at completion (EAC) for over target baseline (OTB) contracts. Using contract performance report (CPR), data, we adopted the Gompertz Growth Curve Model to produce three EAC models: a production model, a development model, and a combined model. We used the mean absolute percentage error (MAPE) to evaluate the developed models. For 63% to 78% of OTB contracts, depending on model, the Gompertz Growth Models out-performed all three index-based methods for predicting the EAC.