Normalization Methods Applied to the Life Cycle Impact Assessment Phase: A Systematic Literature Review

Objective: This study aims to synthesize evidence, identify research gaps, and provide a framework on normalization methods in Life Cycle Impact Assessment (LCIA). Theoretical Framework: Normalization is a tool used in Life Cycle Assessment (LCA) to calculate the magnitude of results obtained in category indicators. Although optional in LCIA, it can assist in interpreting the results. Method: The research adopts a Systematic Literature Review (SLR) to identify the most applied normalization methods in product impact assessment and to present general information about their characteristics and requirements. Results and Discussion: The results reveal a diversity of normalization methods in LCIA, highlighting Global Normalization, Regional Normalization, and Planetary Boundaries. This trend indicates a growing concern in aligning impact assessments with global and regional sustainability standards, reflecting the advancement of the debate on environmental limits. Research Implications: This study significantly contributes to the existing literature. The selection and application of normalization methods, especially Global Normalization, Regional Normalization, and Planetary Boundaries, encourage further research in LCIA, promoting the adoption of more significant indicators. Originality/Value: This study presents a comprehensive SLR and a bibliometric analysis of normalization methods in LCIA. It outlines the current landscape and guides other researchers, highlighting the relevance and value of the most adequate and significant normalization methods.