Evaluating Interactions between Formwork System Selection Criteria for Building Construction Projects: A Rough DEMATEL Approach

This study aims to improve the decision-making process for selecting formwork systems (FWS) in building construction projects by addressing the subjectivity and uncertainty of expert judgments. It seeks to uncover the complex interactions among FWS selection criteria and identify the critical criteria that may influence the decision-making process of FWSs. To achieve this, the study proposes the rough decision-making trial and evaluation laboratory (R-DEMATEL) method, which merges DEMATEL with rough set theory, to unravel the cause-and-effect relationships within FWS selection criteria. The research methodology is divided into two stages. First, the FWS selection criteria for the building construction project are determined based on literature review and expert opinion. Subsequently, the R-DEMATEL method is employed to assess the interactions among FWS selection criteria and depict their causal relationships. Furthermore, the critical criteria are determined according to their ranking. Applying the R-DEMATEL method in a building construction project in Turkiye identified key relationships among FWS selection criteria. The study revealed that the initial cost of the FWS, its flexibility, compatibility with the structural slab, degree of repetition, hoisting equipment, and total building height significantly affect the speed of construction and labor-related performance metrics. In addition, five critical criteria- labor cost, labor productivity, initial cost of the FWS, speed of construction, and labor quality- are emphasized as paramount, consistent with recent studies conducted in the Turkish building construction sector. The literature has largely ignored the impact of expert opinion subjectivity and uncertainty in FWS selection criteria evaluation. This study contributes to the existing literature by highlighting the crucial interactions among FWS selection criteria and suggests using the R-DEMATEL method for a more informed and nuanced FWS decision-making process. Practical Applications This study provides construction professionals with practical insights to improve the FWS selection process in building construction projects. The results indicate that the initial cost of the FWS, its flexibility, compatibility with the structural design, degree of repetition, hoisting equipment requirements, and total building height are the critical criteria that affect labor-related metrics (i.e., productivity, cost, and quality), speed of construction, and overall project performance. Practitioners may leverage these valuable insights to select FWS alternatives that provide improved adaptability and better alignment with project-specific structural requirements, thus enhancing constructability and reducing total project costs. Identifying the interdependencies among FWS selection criteria underlines the necessity of a comprehensive strategy and early stakeholder involvement throughout the initial planning and procurement phases in the FWS selection process. Practitioners are encouraged to evaluate how the critical criteria influence subsequent construction activities rather than considering each criterion in isolation. Proactively considering these influential criteria may enable construction teams to improve labor efficiency, control scheduling risks, reduce cost, and achieve better project outcomes. By combining rough set theory and the DEMATEL method, this study effectively maps the cause-effect relationships under uncertainty, thereby revealing the interactions among FWS selection criteria. Practitioners may use the results of this comprehensive view to anticipate possible project performance constraints and make informed decisions that may balance the initial investment with operational efficiency throughout the project lifecycle.