Sources of Changes in Design-Build Contracts for a Governmental Owner

Use of design-build contracting has been gaining popularity for government procurement of construction. An oft-touted advantage is fewer change orders due to design errors, since the designer (A/E) and contractor are one entity. A comparison of transportation-related design-build projects with roughly comparable design-bid-build (traditional) contracts indicated there was little difference in the amount of change orders and their cost. Overall, recent literature presents little statistically sound evidence that design-build contacting "reduces cost growth." Changes might arise from: owner- requested additions or deletions to the work; the actions of third parties beyond the control of the owner or contractor; delays in owner-supplied access, permits, or equipment; differing site conditions; as well as discrepancies in the original design-build specifications that the owner developed to form the basis for the request for design-build proposals. This research reports on the changes in twenty-three government design-build construction projects, and categorizes their causes. Overall, the number of changes due to design error in design-build construction is statistically significantly lower than that of the traditional design-bid-build construction. Design-build construction also experiences a lower number of changes in sources other than design error, albeit not statistically significant.