Abstract
Construction delays are common in the construction industry in Saudi Arabia. This study aims to develop a simulation forecasting model for the delay time in Saudi projects by considering ten previously identified factors. This study employs a systematic, integrated approach of the decision-making trial and evaluation laboratory (DEMATEL) methodology and system dynamics (SD) to reflect the ten factors that impact project delay. The DEMATEL technique is used in this study to solve the difficulty of systematically developing a causal loop diagram within the SD modelling process. The developed SD model is tested for consistency and extreme conditions. It is then validated and applied using three case studies (an academic building, administrative building, and infrastructure project) in Saudi Arabia by comparing the actual and fitted progress curves of each case study. The results show that the proposed model can be a respectable aid to project managers in forecasting Saudi projects wherein the actual monthly progress follows an S-curve. In this regard, three satisfaction conditions are introduced to check the project progress in the S-curves. In addition, this study provides a systematic approach combining the DEMATEL and SD techniques, which can simplify the SD modelling process in the future. Furthermore, the study methodology can be repeated in other countries.