Portfolio optimization of prefabricated interior building component systems: A multistakeholder perspective

Prefabrication, although increasingly studied and applied in structural components, remains underdeveloped for interior building systems due to limited evidence of benefits, cost uncertainties, and diverse stakeholder preferences. However, existing studies lack an effective framework to assess the cost-benefit performance of these systems and to incorporate stakeholder considerations into system-level, component-based decision-making. To address this issue, this study proposes a framework to assess the costs and benefits of interior building component systems and to optimize their portfolio based on multistakeholder consensus. First, this study assessed the objective benefits and costs of key stakeholders, which then were transformed into subjective benefit and cost prospects using prospect theory. These values subsequently were incorporated into a multiobjective optimization model to identify Pareto-optimal portfolios of interior building component systems. Finally, Euclidean distance was employed as the primary consensus metric for Pareto solutions, and alternative distance metrics were used for robustness checking. The results show that prefabricated interior partition walls, false ceilings, radiant heating and flooring systems, and bathrooms outperform in situ methods in accessibility, adaptability, and construction duration but not across all criteria, suggesting that a hybrid combination aligns technical feasibility with performance demands under varying project conditions. The multiobjective optimization model yielded nine Pareto-optimal solutions. Among them, the configuration combining in situ interior partition walls, radiant heating and flooring with prefabricated false ceilings and bathroom units achieved the highest degree of consensus, despite imposing an additional cost of CNY 3,982.48/dwelling for residents and building-level increases of CNY 91,948.56 and 53,043.20 for the government and contractors, respectively, compared with the prevailing configuration. This outcome is driven by the greater expected benefits delivered by this configuration for all stakeholders, as well as the insufficient benefit performance of the prevailing configuration. The novelty of this study lies in the innovative integration of prospect theory into a multiobjective optimization framework for interior building component systems, enabling the modeling of stakeholders' bounded rationality and heterogeneous preferences under uncertainty to support portfolio decision-making. The proposed framework facilitates data-driven decision-making in interior building component systems that respects stakeholder priorities, adheres to financial constraints, and fosters basic consensus among all parties.