An MCDM Workflow for AEC Stakeholders’ Collaboration at Early Stage: developing a computational tool for MMC projects

Decisions regarding the adoption of Modern Methods of Construction (MMC) are commonly made through linear and sequential design workflows. In such processes, architectural decisions are often established before fabrication and engineering stakeholders are actively involved. This sequencing restricts concurrent stakeholder participation and limits opportunities to negotiate trade-offs across disciplines. As a result, MMC options that may better balance architectural intent, fabrication feasibility, and engineering requirements are frequently excluded at an early stage. This study addresses this limitation by proposing an Multi-Criteria Decision Making (MCDM) based decision-support workflow that enables early and parallel consideration of multiple stakeholder perspectives. Action Research is adopted as the methodological framework, allowing the workflow to be iteratively developed, applied, and refined within real decision-making contexts. The proposed workflow builds upon established MMC evaluation criteria and integrates explicit stakeholder weighting, aggregation, and sensitivity analysis to support the exploration of preferences rather than the identification of a single optimal solution. A computational implementation within a parametric design environment supports scenario generation and parameter extraction at the concept stage, while maintaining a clear separation between design generation and decision logic. An illustrative case study demonstrates how the workflow facilitates concurrent stakeholder engagement and reveals how decision outcomes vary under different priority settings. The findings suggest that embedding flexible, preference-aware decision-support processes at early design stages can improve transparency, encourage cross-disciplinary dialogue, and reduce the risk of prematurely excluding viable MMC options.