A Comparative Analysis of MCDA Methods for Safe and Sustainable by Design Assessment

Abstract

The Safe and Sustainable by Design (SSbD) framework is central to the European Union's cleaner and safer production and chemical sustainability goals, necessitating robust tools for implementation. This paper presents a review and comparative computational analysis of Multi-Criteria Decision Analysis (MCDA) methodologies for SSbD. Standard fully compensatory fully compensatory MCDA methods are shown to be fundamentally unsuitable as primary safety gates in regulatory decision contexts because they permit high sustainability performance to offset critical safety hazards, conflicting with the non-compensatory principle of chemical safety legislation like REACH. Three approaches were mathematically formulated and evaluated using a plasticizer case study: compensatory composite indicators, the regulatory-aligned multiple-criteria decision analysis for assessments of chemical alternatives (MCDA-ACA), and the Joint Research Centre (JRC) quantitative SSbD framework. The analysis demonstrates that compensatory methods fail to reliably implement safety-first logic at the gate, while non-compensatory or hybrid frameworks such as MCDA-ACA, the JRC method, and the CI-SSbDC composite indicator successfully implement safety-first logic through discrete value functions, minimum aggregation, and explicit cut-off criteria. We recommend a robust, two-stage hybrid approach for practitioners: (1) apply a validated non-compensatory safety gate to eliminate hazardous alternatives, and (2) subsequently rank the remaining safe options using comprehensive sustainability and performance criteria. This work contributes to operationalizing SSbD by providing a clear and validated methodological pathway for informed decision-making in cleaner chemical innovation