A Modification of the WSM for Generating Evaluations from Objective Data and DMs’ Subjective Preferences: A Case Study of Photovoltaic Modules Replacement in a Public Building

This study proposes a modification of the Weighted Sum Model (WSM) that formalizes the evaluation generation for alternatives. By integrating objective data with decision-makers’ (DMs’) subjective preferences, the modification addresses a gap in the classical WSM, where evaluations are traditionally assigned subjectively, despite the availability of measurable data describing the alternatives. The modification introduces a structured mechanism for handling heterogeneous data by distinguishing between numerically represented and matrix-represented criteria. The quantitative criteria are processed through normalization procedures aligned with individual DMs’ preferences. Meanwhile, the qualitative characteristics are decomposed into sets of options and structured as binary matrices. The applicability of the modified model is demonstrated through a case study on replacing photovoltaic modules in a public building. Results indicate that changes in DMs’ preferences lead to observable differences in the generated evaluations and in the ranking of the alternatives, even when identical objective data is used. Ultimately, these results demonstrate that the modified WSM improves the flexibility and transparency of the decision-making process, providing a more realistic representation of experts’ preferences. From a sustainability perspective, it facilitates more informed and balanced decisions in the management of energy systems and public infrastructure.