Determinants of variation orders and their impact on cost overrun in coastal construction projects: A case study in Bali, Indonesia

Abstract

Cost overruns remain a persistent challenge in construction projects, particularly in environmentally complex settings such as coastal areas. This study aims to analyse the determinants of variation orders and their impact on cost overruns in coastal construction projects, using a case study in Bali, Indonesia. A quantitative approach was adopted, with data collected through structured questionnaires from 30 construction professionals, including project managers, engineers, and quantity surveyors. The data were analysed using multiple linear regression to examine the influence of design, specification, safety, and scope-related factors on cost overruns. The results indicate that variation orders have a significant effect on cost overruns, both simultaneously and partially. Among the examined variables, scope changes were identified as the most dominant factor, followed by design, safety, and specification factors. These findings suggest that instability in project scope, combined with design revisions and operational adjustments, plays a critical role in driving cost escalation. Importantly, this study reveals that variation orders in coastal construction projects are not solely driven by internal project factors but are also strongly influenced by environmental uncertainty, such as tidal conditions, shoreline dynamics, and regulatory requirements.&nbsp