Indices, the combination of multiple indicators into a single score, are common products of risk and vulnerability assessments to compare countries or other entities, often in the form of rankings or maps . They can indicate changes in vulnerability over time within their respective conceptualisation of vulnerability or risk. The construction of indices, including indicator selection, their weighting, normalisation and data sources, has a profound impact on their scores . Research has consistently found large discrepancies between country vulnerability rankings . Reviews of vulnerability and resilience indices identified 'substantial conceptual, methodological and empirical weaknesses'  and a widespread lack of validation . Using countries as a unit of analysis also masks significant sub-national variation . Individual indices therefore 'fail to convene a robust guidance for policy makers'  and should not present the sole basis for policy decisions . Due to their limitations , the OECD suggests that indices are primarily used for 'initiating discussion and stimulating public interest' .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report