New Report on Environmental Decision Making under Uncertainty

A new report has been published by the Institute of Medicine (IOM) of the National Academy of Sciences to provide guidance to decision makers in the U.S. EPA and their partners in states and localities on approaches to managing risk in different contexts when uncertainty is present. The U.S. EPA and other government agencies have the mission to estimate risks to human health and the environment, to identify the potential regulatory actions to mitigate those risks, and then to use that information to enact appropriate regulations. That decision-making process requires consideration of many factors including health risk assessment (historically EPA’s main focus), economic, technological, social and political. All those factors introduce multiple sources of uncertainty into the decision-making process. Although seemingly daunting, the report recommends that as a first and critical step, the decision-making process needs to identify key uncertainties. The report committee classifies the various types of uncertainty into three major categories: (1) statistical variability and heterogeneity (also called aleatory or exogenous uncertainty),(2) model and parameter uncertainty (also called epistemic uncertainty), and (3) deep uncertainty (uncertainty about the fundamental processes or assumptions underlying a risk assessment). The types and source of uncertainty are often key determinants of the appropriate type of uncertainty analysis. The committee provides guidance on how uncertainty analyses about health effects, technological availability, and cost can be used in the decision making process. The report also points out that just as important as the uncertainty analysis is how information on uncertainty should be presented to help risk managers make sound decisions and to increase transparency in its communications with the public about those decisions. Finally, the report committee makes recommendations on ways to improve the identification, analysis and communication of uncertainty in the decision-making process.

As environmental litigation consultants, L. Everett & Associates understands the challenges of uncertainty.  Our cases and projects normally require the assessment of multiple sources of information and numerous quantities of datasets, each with its unique associated uncertainty. As recommended in the IOM report, we strive to identify and analyze uncertainty in each case to make the best possible informed decision how, when and where to invest resources to reduce the uncertainty. We have developed and use tools such as 3D data visualization models to effectively communicate uncertainty and complex environmental and hydrogeologic concepts to all stakeholders.