Interpretive Structural Model-based for Analysis of Causes of Delays in Construction Projects: The Portuguese Case

Delays are a common issue in construction projects worldwide, and they can frequently have an influence on time and cost overruns, among other problems. This study aims to add to the knowledge on construction project management theory and practice by identifying the leading causes of Delays in Construction Projects (DCP) in Portugal, modeling their interrelationships, and determining their main causes. The study presented herein adopted a two-phase methodology. First, based on the literature, the causes of DCP in Portugal are identified. Then the hierarchical structure of the causes of DCP is determined, using integrated Interpretive Structural Modelling (ISM), and an ISM-based Model is developed. The results show that the 16 causes of DCP taken into consideration are hierarchized in six different influence levels. The causes Bidding and contract award process and Lack of communication between parties are the most influential causes, and are thus considered to be the root causes of DCP in Portugal. Additionally, the results show that the causes of DCP can be divided into four different categories relating to Relationships and contract, Material, the Developer, and the Contractor. Finally, these results provide fundamental insights for practitioners and researchers to develop effective measures to mitigate the causes of DCP.