Quantitative Comparison of Project Performance between Project Delivery Systems

Abstract

A project delivery system (PDS) defines the relationship and timing of involvement between different contracting parties in construction. Using data from 109 projects, this paper statistically investigates the project performance of the four main PDSs: design-bid-build (DBB), construction management (CM), design-build (DB), and integrated project delivery (IPD). First, descriptive statistical methodologies were applied to the dataset to determine performance benchmarks for each examined PDS. Next, by applying statistical tests, such as the analysis of variance (ANOVA) F-test and the Kruskal-Wallis H-test, statistically significant performance differences among the examined PDSs were identified in five performance areas: cost, schedule, quality, communication, and change management. Finally, pairwise comparisons were performed by applying posthoc statistical tests to each pair of PDSs, demonstrating that IPD outperformed DBB in 11 metrics, while it outperformed CM and DB in two metrics each. Also, DB outperformed DBB in seven metrics, and CM outperformed DBB in five metrics. This paper addresses a consistently missing piece in the existing body of literature related to project delivery. The findings presented in this paper should prompt industry leaders and professionals to move away from the DBB model and toward IPD and other synergic PDSs.