DBFM-projects have a significantly better cost performance than D&C-projects.•
DBFM-projects especially have high performance regarding technical necessities.•
D&C-projects have higher cost performance regarding scope adjustments.•
Scope adjustments are the main reason for contract change costs across projects.
An important reason to procure transport infrastructure projects through Public-Private Partnerships (PPPs) is that they are expected to have a better cost performance compared to regular infrastructure procurement. However, the evidence for this is weak. Therefore, this article analyzes the cost performance (in terms of costs for additional work caused by contract changes during project implementation) of Design-Build-Finance-Maintain (DBFM) projects versus Design and Construct (D&C) projects. DBFM is considered a type of PPP and D&C is not. Data were collected on 58 projects from the Project Database of Rijkswaterstaat and analyzed using non-parametric tests. The results show that DBFM-projects have a significantly better cost performance than D&C-projects, especially concerning costs for additional work due to technical necessities. Because scope adjustments are the main reason for contract changes across the D&C- and DBFM-projects, cost performance can be improved particularly by curbing scope adjustments costs.