The Environmental Performance Index is released biennially by Yale University. The EPI and the Pilot Trend Environmental Performance Index (Trend EPI) rank countries on 22 performance indicators spanning ten policy categories reflecting facets of both environmental public health and ecosystem vitality. The methodology facilitates country comparisons and provides a way to assess the global community’s performance over time with respect to established environmental policy goals. The EPI’s quantitative approach allows policymakers and other experts a comparative understanding of environmental performance relative to other countries.