Journal of Construction in Developing Countries, 24(2), 1–22, 2019 © Penerbit Universiti Sains Malaysia, 2019. This work is licensed under the terms of the Creative Commons Attribution (CC BY) (http://creativecommons.org/licenses/by/4.0/). Interface Problems in Change Order-Challenged Projects * Puti Marzuki, Adrianto Oktavianus, Almerinda Regina, Budi Hasiholan and Meifrinaldi Published online: 31 December 2019 To cite this article: Puti Marzuki, Adrianto Oktavianus, Almerinda Regina, Budi Hasiholan and Meifrinaldi (2019). Interface problems in change order-challenged projects. Journal of Construction in Developing Countries, 24(2): 1–22. https://doi. org/10.21315/jcdc2019.24.2.1. To link to this article: https://doi.org/10.21315/jcdc2019.24.2.1 Abstract: Change orders are among the main sources of problems challenging timely completion of construction projects. The signifcantly needed conducive interaction among project participants to mitigate completion delay risk due to change orders is often hampered by interface problems. This article describes potential sources of interface problems and their role in affecting completion time of change order-challenged infrastructure construction projects in Indonesia. The identifed sources then serve as inputs to formulate a systems thinking model of relational interface problems in change order-challenged projects. A survey of eleven important infrastructure construction projects was conducted to obtain data on the main sources of these interface problems and their severity indexes. A second survey was later conducted to perceive the most frequent causes of change orders, the infuence of interface problem cause factors on the length of change order process and the infuence of interface problem cause factors on the expediting capacity of a project team and ultimately induce a delay of project completion. The results of both surveys then served as inputs to a systems thinking structure showing the factors in a change order-challenged project. The study shows that contract, technical experience, management, coordination and fnancial aspects are the potential sources of interface problems in Indonesian infrastructure construction projects. In a change order-challenged project, these interface problems' sources will complicate the efforts to achieve the project's time objective. The study especially points out the role of contract documents' quality in increasing the likelihood and extent of change orders and the infuence of workers' productivity in mitigating the negative impact of a change order. Keywords: Interface problem, Delay, Construction project, Change order, Indonesia INTRODUCTION Organisational interactions among parties involved in a construction project are known to create relational interfaces. Relational or organisational interfaces are considered as links between these parties. Due to its multiple numbers of involved parties, participants or stakeholders, a construction project is said to be fragmented. Anumba, Kamara and Cutting-Decelle (2007) found that this fragmentation may lead to misperceptions and misunderstandings. Interface problems occur when a construction project's objective fulflment depends on the interaction of two or more stakeholders in this fragmented environment. Meanwhile, change, defned as any event that results in modifcation of the original scope, execution time or cost of work, is inevitable on most construction projects due to the uniqueness of each project and the limited available resources Faculty of Civil and Environmental Engineering, Institut Teknologi Bandung, INDONESIA *Corresponding author: puti@si.itb.ac.id