Impact Analysis of Cost and Quality on Project Duration Using SEM—A Data Driven Decision Support Model for Fast-Track Building Projects

Time overrun and tight deadlines set by the client are the critical challenges faced by the construction industry for decades. The fast-track technique was introduced to overcome these challenges. Since its introduction in 1970s, a number of construction projects have been completed on fast-track however the stakeholders still lack confidence in its implementation, mainly due to the lack of awareness of the impact that variances in cost and quality have on project duration on fast-track schedule and the lack of decision support available in this domain. This research aims at analysing the impact of cost and quality variances on project duration thereby proposing a decision support model that facilitates the decision-making process. Data was gathered from 159 construction industry professionals on a 5-point Likert scale based questionnaire. Structural equation modelling (SEM) software was used to analyse the data. 4 hypotheses were developed including the mediation analysis. The results of the analysis showed that both cost and quality variances have significant impact on variances in project duration. Moreover, the quality variance also significantly impacts the variations in project budget. The mediation analysis showed that cost variance mediates a statistically significant impact between variations in project quality and project duration. The R2 values of the proposed model indicated that 78.4% of the changes in project duration are attributed to changes in project cost and quality whereas 72.9% variations in project cost are attributed to changes in project quality. The IPMA results showed that the decisions resulting in variations in project cost have the greatest potential to enhance project performance in terms of project duration among which adopting scope freeze approach at early design stage, over-designing the facility and early procurement of long-lead-time items are the most influential decisions whereas over-extending the resources on quality related decisions may result in adverse effects on project duration which include early involvement of O&M team in design phase, early involvement of the contractor in design phase, 90% acceptable quality compromise and quality management plan submission in pre-design stage. Q2, RMSE, MAE and CVPAT values confirm that the proposed model has high out-of-sample predictability.