source use and product manufacture that are likely to be more sustainable—a criterion that includes health and environmental factors but others as well. Moreover, decisions in EPA often require consideration of difficult questions of costs, benefits, and risk-risk tradeoffs. Much of the discussion of Chapter 7, for example, revealed the difficulties encountered in current approaches as attempts are made to apply them to complex problems of cumulative and communitywide risks.

As the complexities of the problems and of needed decisions faced by EPA increase, so do the challenges to risk assessment to provide evaluations of clear relevance to the questions posed. That means, of course, that the questions posed to risk assessors must be both relevant to the problems and decisions faced and sufficiently comprehensive to ensure that the best available options for managing risks are given due consideration. This chapter provides guidance on the development and application of questions, methods, and decision processes to enhance the utility of risk assessment; although many elements of the guidance are applicable in the near term, our emphasis is on the longer-term future.


The model described in Risk Assessment in the Federal Government: Managing the Process (NRC 1983), referred to as the Red Book, was discussed in Chapters 1 and 2; in this model, risk assessment occupies a place between research and risk management. Risk assessment is seen as a framework1 within which complex and often inconsistent, and always incomplete, research information is interpreted and put into usable form for risk managers. The Red Book committee was concerned principally with defining risk assessment and identifying the steps necessary to complete an assessment. It was also concerned with ensuring that risk characterization (the fourth and final step) is faithful to the underlying science and its uncertainties. Finally, and perhaps most important, the committee was concerned with protecting risk assessments from the inappropriate intrusions of policy-makers and other stakeholders, and from that concern came recommendations for the conceptual separation of assessment and management and for the development of risk-assessment guidelines and the elucidation and selection of “inference options” (defaults; see Chapters 2 and 6). Those and other recommendations of the Red Book have served for 25 years as sources of clarity and guidance for regulatory and public-health officials throughout the world and for stakeholders of many types.

The present committee supports retention and advancement of the major recommendations of the Red Book as they pertain to definitions, the content of risk assessment, the need for guidelines and defaults, and the conceptual separation of assessment from management. Many of our recommendations advance those aspects of the recommendations in the Red Book (and the National Research Council’s 1994 report Science and Judgment in Risk Assessment).

To the extent that risk assessment is perceived as becoming less relevant to many important decisions or as contributing to protracted scientific debate and regulatory gridlock, that perception may result from interpretations of the Red Book that take the conceptual distinctions and separations as representing the committee’s guide to a preferred decision-making process. In fact, the Red Book’s concern with “process” focused heavily on protecting the integrity of risk assessment, and the committee offered little discussion of how all the necessary elements of decision-making should be arranged to achieve good decisions. That


The term framework as used here refers to the entire decision process, of which risk assessment is one element. Risk assessment has its own framework, as described in Chapters 1 and 2 and the Red Book.

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