Measuring the Unseen: A Systematic Review of Biodiversity Risk Assessment

This review systematically synthesizes biodiversity risk measures into three categories: text-based indicators, condition-based indicators, and expenditure-based indicators. For each category, we summarize the construction logic, data sources, and application scenarios. We further identify key research gaps, including the lack of a unified framework to distinguish physical from transition risks, insufficient outcome-based indicators, untested predictive validity, and technical questions in standardization and frequency. This review serves as a useful reference for investors, policymakers, and researchers, while also outlining directions for future methodological development.