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EXPORT DATE: 19 June 2026

@CONFERENCE{Song2026,
author={Song, Junting and Jaramillo, Daniel Esmeral and Lu, Yu-Peng and Eskew, David and Abandoh, Christopher and Nguyen, Tran and Pishdad, Pardis and Zeng, Qinghao },
editor={Hamzeh, Farook and Poshdar, Mani and Garcia-Lopez,, Nelly P. },
title={Schedule delay in construction delivery methods under extreme uncertainty}, 
journal={Proceedings of the 34th Annual Conference of the International Group for Lean Construction (IGLC 34)}, 
booktitle={Proceedings of the 34th Annual Conference of the International Group for Lean Construction (IGLC 34)}, 
year={2026},
pages={655-667},
url={http://www.iglc.net/papers/details/2590},
doi={10.24928/2026/0315},
affiliation={School of Building Construction College of Design, Georgia Institute of Technology, Atlanta, Georgia,  jsong600@gatech.edu ; School of Building Construction College of Design, Georgia Institute of Technology, Atlanta, Georgia, djaramillo30@gatech.edu ; School of Building Construction College of Design, Georgia Institute of Technology, Atlanta, Georgia,  ylu793@gatech.edu ; School of Building Construction College of Design, Georgia Institute of Technology, Atlanta, Georgia, deskew3@gatech.edu ; School of Building Construction College of Design, Georgia Institute of Technology, Atlanta, Georgia, jcabandoh3@gatech.edu ; Part-time Lecturer, School of Building Construction, College of Design, Georgia Institute of Technology, Atlanta,  Georgia, dnguyen458@gatech.edu ; Professor, Graduate Program Director; Director, Smart Built Environment Eco-System (Smart Bees) Laboratory,  School of Building Construction, College of Design, Georgia Institute of Technology, Atlanta, Georgia,  pardis.pishdad@design.gatech.edu  ; School of Building Construction, College of Design, Georgia Institute of Technology, Atlanta, Georgia,  qzeng41@gatech.edu  },
abstract={Increasing global disruptions, such as pandemics, trade policy shifts, and supply chain shocks, have intensified uncertainty in construction project delivery. Yet much prior research has examined how project delivery method selection influences project outcomes under conventional conditions, with limited attention to performance under extreme uncertainty. This exploratory comparative study examines schedule delay performance across four delivery methods, Design–Bid–Build (DBB), Design–Build (DB), Construction Manager-at-Risk (CMAR), and Integrated Project Delivery (IPD), with the COVID-19 period (2020–2022) serving as an empirical case of extreme uncertainty. Using publicly verifiable multi-source project documentation, including Federal Emergency Management Agency (FEMA) disruption records, Engineering News-Record (ENR) reports, and project documentation, this study compiled a dataset of 17 non-residential construction projects using a self-defined, normalized Uncertainty Schedule Delay Index (USDI). Descriptively, within this dataset, more collaborative delivery methods, such as IPD and CMAR, tended to show lower schedule delays than DBB and DB. To contextualize these findings, practitioner insights were collected through interviews highlighting early engagement, proactive procurement, and effective team communication. Together, these findings contribute exploratory comparative evidence on delivery method performance and offer practical insights for schedule risk management under extreme uncertainty. },
author_keywords={Collaboration, integration, schedule delay, uncertainty, Integrated Project Delivery (IPD). },
address={Singapore, Singapore },
issn={2789-0015 },
publisher={ },
language={English},
document_type={Conference Paper},
source={IGLC},
}