Assessing the impact of excluded risks on cost and time of construction projects in Samarra using the relative importance index (RII)

This study examined the impact of excluded risks on the cost and schedule performance of construction projects in Samarra, a city affected by persistent security-related challenges. A quantitative research approach was adopted using a structured questionnaire distributed to 49 engineers and construction experts from different engineering disciplines. The collected data were analyzed using the Relative Importance Index (RII) to evaluate excluded risks in terms of likelihood of occurrence, impact on project cost, and impact on project duration. The results indicated that security-related risks, particularly those associated with war conditions and civil disturbances, were perceived as the most critical, with RII values exceeding 0.70 in several cases. In contrast, risks related to partial occupation of projects by the employer, contract-driven design constraints, and nuclear-related considerations were assessed as less significant, with RII values generally below 0.50. The findings also showed that contracts incorporating proactive risk mitigation measures were perceived as more effective in reducing cost overruns and schedule delays than traditional insurance-based risk allocation approaches. The study concluded that improving construction project performance in security-dominant environments requires preventive contractual strategies, locally adapted risk management frameworks, and continuous professional training for engineers and contractors.