Critical Causes of Schedule Delays in Marine Construction Projects: A PMBOK-Structured Assessment Validated Against Documented Outcomes

Schedule overruns in marine construction are pervasive, and on a given project, they typically exceed the cost deviation recorded on the same work. This study identifies the causes of those overruns and establishes their relative criticality for the schedule dimension on its own. A three-tier literature review and a three-round Delphi process produced 173 candidate delay causes, which were organized under the eight performance domains of the PMBOK Guide (Seventh Edition). Criticality was measured with a paired probability-impact index, and stress was tested with a 50,000-run Monte Carlo simulation. The ratings of 200 industry practitioners were ranked and compared between stakeholder roles and experience bands with the Kruskal-Wallis test under false-discovery-rate control. The perception ranking was then set against the documented outcomes of 59 completed marine projects in Egypt and the Gulf, where delays averaged 41.5% of planned duration and reached 100%. The leading causes were escalation in resource prices, delays in work and labor permits and licenses, long-term beach erosion, and delayed geotechnical and bathymetric surveys. Delay magnitude tracked the breadth of co-occurring causes (Spearman’s ρ = 0.76) far more closely than project size or duration. The sharpest discriminators of severe delay were permit delays, skilled-labor shortages, subcontractor delivery failures, and the financial standing of owner and contractor. Environmental uncertainty supplied over a quarter of all documented delay evidence, which indicates that the marine environment acts mainly as a schedule risk. Perception varied more with professional experience than with organizational role.