Comparing Stakeholder-Driven and Data-Driven Weighting for Sustainable Consumer Product Design Using Environmental and Economic Life-Cycle Evidence

Designing consumer products with lower environmental impact and acceptable cost requires designers to interpret life-cycle evidence across competing alternatives. This study compares two contrasting weighting approaches for multi-criteria decision-making in sustainability-focused consumer product design: the stakeholder-preference-driven Analytic Hierarchy Process (AHP) and the data-driven Criteria Importance Through Intercriteria Correlation–Technique for Order of Preference by Similarity to Ideal Solution (CRITIC–TOPSIS) method. An electric-bike case study was constructed from 24 feasible configurations defined by frame material, battery type, tire material, and coating method. Environmental performance was quantified using Life Cycle Assessment (LCA) with ReCiPe midpoint indicators, and economic performance was represented using a component-level life-cycle cost proxy. The methods identified broadly similar high- and low-performing regions of the design space, but they differed in the ranking of specific alternatives. Statistical comparison showed strong agreement among the ranking methods, although differences remained in the exact ordering of some alternatives. These findings show that weighting methods do not determine product sustainability on their own; rather, they shape how environmental and economic evidence is translated into design decisions. For consumer product development, AHP is useful when stakeholder priorities must be made explicit, whereas CRITIC–TOPSIS is advantageous when repeatable data-driven screening is needed.