Comparative Risk Assessment

Abstract Comparative risk assessment is an analytic process of evaluating and ranking the different factors that contribute to a particular outcome, such as human disease. The term comparative risk assessment is most frequently used in the context of environmental risk, but the principles and methodology are applicable in other contexts. Comparative risk assessment is both a scientific and political process. Scientific methods are used to gather data, classify the type and severity of risks, and identify and verify relationships between outcomes and risk factors. As it is a guide to decision making, comparative risk assessment also involves the political functions of defining the scope of the assessment, involving stakeholders in the process, and putting the results into a context that can be used to develop consensus concerning appropriate action. This article reviews the history of comparative risk assessment for environmental risk, discusses methods of risk ranking used in environmental risk, reviews methods of communicating risk, considers a few examples of comparative risk assessment in nonenvironmental areas, and touches on United States Environmental Protection Agency (USEPA) and other regulations as they relate to comparative risk assessment.