Faranak Zagia, Stephen L. Kajewski, Sara Omrani, Omid Motamedisedeh
The construction industry is a key sector driving global economic growth. Despite advancements in managerial models, it continues to face challenges, notably delays and underperformance in projects, a persistent issue worldwide. This study offers a comprehensive review and analysis of primary causes of delays in construction projects across various countries, using the PRISMA method. The research makes key contributions: a) Identifying primary causes of delays in different project types, including residential buildings, public buildings, transport infrastructure, and other infrastructure projects; b) Comparing delay causes across 35 countries; c) Evaluating the most commonly used decision-making models for prioritizing delay risk factors; and d) Ranking causes of delays in construction projects based on 92 studies. Findings show that while delay causes vary by country and project type, certain factors—such as financial issues with the owner and delayed contractor payments—are widespread. Transport infrastructure projects are particularly affected by poor site conditions, topographical challenges, and weak project management. Residential projects often face delays due to changes in owner requirements and execution errors, while public buildings and other infrastructure projects suffer from inaccurate time estimations. This study provides valuable insights into the complexities of project delays and offers guidance for improving project management practices to mitigate delays.