Modelling Variation for Improving the Management of Construction Engineering Project Outcomes in the Kingdom of Saudi Arabia

Abstract

One common theme in the international construction sector is variation in projects, which has influences on construction project outcomes. This study argued that variation can take place during all phases of a construction project and can be defined as any change during the project life cycle that might affect the contracted cost, time, quality or scope parameters. From the wide literature review of previous studies that has been conducted on variation in construction projects, it was found that there was a gap in estimating the influence of variation on construction project outcomes in terms of duration and cost overruns. Therefore, the main aim of this research was to propose a model that could be used to estimate the influence of variation causes on construction project outcomes in the Kingdom of Saudi Arabia (KSA) for clients to use, which would lead to a new contribution to the literature in the construction industry. A mixed research methodology was adopted to achieve the aim and objectives of this research. An in-depth literature review has been carried out to synthesise existing knowledge on the sources, causes of variation and their impacts on project success criteria of construction projects in KSA in terms cost, time, quality and scope. This has resulted in the elicitation of a large list of possible causes of variation factors. The list was classified and clustered according to the source of the variation into four homogenous groups. This was then developed into a questionnaire for collecting primary data by using an online survey for this purpose. Several statistical tools were used to analyse the variation in the respondents’ answers to estimate the association between a set of causes of variations and their impact on project success criteria. A regression model to assess the percentage of duration overrun due to causes of variation was proposed utilising the data obtained from 18 project cases from KSA. The model’s independent variables, i.e. the causes of variation, were selected based on their significance and high correlation to the dependent variable (i.e. percentage of duration overruns). To summarise, this research was sought to map project duration overrun into causes of variation and presented an equation of selected regression model that could be used to estimate the percentage of the duration overrun of construction projects in KSA based on the significance influence of certain causes of variation. The model served as a vehicle for assessing the impact of variation on project performance. It also enabled clients and consultants to identify strategies for management variation, and assisted them in identifying the causes that may lead to undermining project performance.