Analysis of the Variability of Project Cost and Schedule Performance in the Design-Build Environment

Abstract

Design-build (DB) projects are getting more implementations in the United States. Several studies indicate that the DB project delivery system has advantages in project cost and schedule performance. Despite having comparative advantages, DB projects are found to be far from immune from cost overruns and schedule delay in those studies. It is critical to understand the effects of various factors underpinning the cost and schedule performance of DB projects. The overall objective of this research is to utilize cluster analysis and statistical analysis to identify factors with significant potentials to describe the variability of project cost and schedule performance in DB environment. Several control factors, such as evolving requirements from owners, unforeseen conditions, attributes of project teams, and major project characteristics were taken into account. This research contributes to the body of knowledge in innovative project delivery through empirical examination of underlying factors affecting project cost and schedule performance. The notable findings are (1) progressive DB is associated with the best cost performance, and its application could effectively reduce owner-directed changes; (2) project managers’ experience, particularly the lack thereof, brings more variability to cost performance, while projects in the places with greater experience with completed projects show greater cost performance; (3) the effects of contract and procurement method on cost performance are significantly moderated by project and owner types; (4) unforeseen conditions are not necessarily related to cost performance; and (5) some unforeseen conditions (i.e., unforeseen inclement weather and unforeseen interruptions from government) are found to have statistically significant negative implications on schedule performance.