Institutional gatekeeping and change order prevention in public infrastructure projects: evidence from a governance reform in Jordan

This study examines change order behavior in public road infrastructure as a two-stage process separating occurrence from conditional severity. Using an official dataset of 157 projects in Jordan (116 pre-policy, 41 post-policy), the analysis applies exact nonparametric inference and a two-part modeling framework suited to zero-inflated, heavy-tailed outcomes. Results reveal a sharp structural shift following governance reform: nonzero-change order occurrence declines from 40.5% to 4.9%, with complete suppression in externally funded projects and near-elimination in the Ministry of Public Works and Housing (MoPWH) funded projects, while decentralized projects show no change. Qualitative evidence further indicates that strengthened approval thresholds act as the primary downstream gatekeeping mechanism, while design accountability and contractor prequalification operate as upstream controls reducing the generation of change-inducing conditions . In contrast, conditional severity remains highly dispersed once changes are approved, indicating limited governance influence at this stage. These findings establish a clear frequency severity separation and demonstrate that governance effectiveness operates primarily through suppressing initiation rather than reducing magnitude, highlighting the limitations of aggregate cost-based metrics in evaluating policy impact.