A quantitative assessment of the cost and time impact of variation orders on construction projects

Purpose – Variation orders are a common occurrence in construction projects and their impacts have been studied by various authors. However, the contribution of project variations to construction cost and time overruns is yet to be established. The purpose of this study is to assess the significance of variations as a cause of cost and time overruns.Design/methodology/approach – Using a questionnaire survey, responses were obtained from 50 project participants on the causes and effects of project variations. Cost and time data were also collected on 30 completed building projects. The analysis used importance indices and F‐ and t‐tests. The results indicated that variations had a significant effect and accounted for about 79 and 68 per cent of the cost and time overruns, respectively, for the projects studied.Findings – The results indicated that variations had a significant effect on project cost and time overruns and accounted for about 79 and 68 per cent of the cost and time overruns, respectively, for...