Factors-driven comparison between BIM-based and traditional 2D quantity takeoff in construction cost estimation

Purpose: Quantity Takeoff (QTO) is an integral part of the decision-making process. Currently, QTO is mostly done using manual or 2D method, and practitioners are considering the use of BIM quantity takeoff as an effective alternative to the traditional 2D software takeoff. However, the existing literature does not have adequate studies to confirm that the use of BIM-based QTO is better than the 2D method. Therefore, this paper aims to expand and improve the existing literature into a more detailed analysis of each element to investigate that BIM is indeed a better option of the two QTO methods. Design/methodology/approach: A total of 19 factors in four broad categories, i.e. timely decision making, accuracy, collaboration, and level of details were identified to draw a significant comparison between the two procedures, i.e. BIM-based quantity takeoff and traditional 2D takeoff. Surveys and case study are used to collect data for analysis to achieve the research goals. Findings: The questionnaire survey showed that using BIM for the QTO process has significant benefits in achieving higher productivity on takeoff, accuracy, clarity and collaboration among the team members. The case study results also showed improvement in BIM-based QTO by achieving higher accuracy and productivity. Originality/value: Understanding the difference between the two QTO processes is a challenging task; therefore, this paper contributes to drawing a comparison line between the two processes by introducing the factors that affect the QTO process.