Handling the Perils of Uncertainty

All risk assessments involve uncertainty, but their conclusions must be defensible. In a situation in which a risk assessment is legally mandated and likely to be challenged in court, defensibility is obviously particularly important.

Therefore, the risk manager and the risk assessor should have a frank and extensive discussion, and be very clear about the sources of uncertainty and the ways in which it can be reduced (if necessary or possible) through selective investment of resources. This is another way in which a tiered assessment can be useful.

Outside Resources: Uncertainty is treated further in documents available on the EPA Web site such as Guidance for the Data Quality Objectives Process (http://www.epa.gov/swerust1/cat/epaqag4.pdf) and Policy for Use of Probabilistic Analysis in Risk Assessment at the U.S. Environmental Protection Agency (http://www.epa.gov/ncea/mcpolicy.htm).

Relevant guidelines section(s): 2.2.3