Project Performance Comparison of United States P3 Building Projects with DB and DBB Building Projects

Public building projects in the United States continue to face challenges related to cost escalation and schedule delays, prompting increased interest in alternative project delivery methods. Although Design–Bid–Build (DBB) remains the most commonly used approach, Design–Build (DB) and Public–Private Partnership (P3) delivery methods are increasingly adopted with the expectation of improved project performance. This study uses three statistical tests to determine whether three performance metrics related to the cost and schedule of U.S. building projects delivered using P3, DB, and DBB are significantly different. Before conducting this test, project costs were adjusted to constant 2025 dollars using the RS Means City Cost Index to account for differences in completion years. On average, all three test results indicate that P3 projects’ cost growth (−2.61%) is significantly lower than that of DB (7.95%) and DBB (24.40%). Similarly, the schedule growth of P3 projects (−2.51%) was significantly lower than that of DB (2.65%) and DBB (27.09%). However, no statistically significant difference in the schedule was observed between DB and DBB. Differences in construction intensity were not statistically significant. These findings provide quantitative insight for owners when selecting delivery methods for building projects.