Sensitivity analysis of the 2008 Environmental Performance Index

An assessment of the robustness of the 2008EPI results requires the evaluation of uncertainties underlying the index and the sensitivity of the country scores and rankings to the methodological choices made during the development of the Index. To test this robustness, the EPI team has continued its partnership with the Joint Research Centre (JRC) of the European Commission in Ispra, Italy. This JRC report shows that the 2008 EPI has an architecture that highlights the complexity of translating environmental stewardship into straightforward, clear-cut policy recipes. The trade-offs within the index dimensions are a reminder of the danger of compensability between dimensions while identifying the areas where more work is needed to achieve a coherent framework in particular in terms of the relative importance of the indicators that compose the EPI framework. The 2008 Environmental Performance Index (EPI) is developed for 149 countries and is based on 25 indicators in six policy categories: Environmental Health, Air Pollution, Water, Biodiversity and Habitat, Productive Natural Resources, Climate Change. The EPI aims to bring a data-driven, fact-based and empirical approach to environmental protection and global sustainability. The validity of the EPI scoring and respective ranking is assessed by evaluating how sensitive the country ranks are to the assumptions made on the index structure and the aggregation of the 25 underlying indicators. The assumptions tested are: - measurement error of the raw data, - choice of capping at selected targets for the 25 indicators, - choice to correct for skewed distributions in the indicators values, - weights of the indicators and/or of the subcomponents of the index, and finally - aggregation function at the policy level (six policy categories).