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Science Policy Tools: Integrated Assessments and Characterizations of Risks
Science policy tools for decision making provide the links between the physical, natural, social, and
economic sciences and environmental policy. Technical assessments are key tools in formulating
national and international environmental policies. To be useful, however, these assessments must be
credible to all stakeholders, including the Administration, Congress, industry, nongovernmental
organizations, and the public.
Research Needs for Science Policy Tools
Develop methods for integrated assessments.
Develop methods for the effective characterization and communication of assessments and uncertainty.
Define criteria and indicators for ecosystem health.
Enhance research on human and ecological exposure.
Continue research on mechanisms of disease and their ecological impacts.
Risk assessment is a systematic process for dealing with uncertainty in decision making and for compiling information on the potential
impact of chemical, biological, and physical stresses on human health, natural resources, and social systems. Risk assessment
provides a framework for organizing and presenting scientific information for making policy and management decisions.
Characterizations of risks may be either quantitative or qualitative, depending on the types of data available and the appropriate
application of risk estimates to decision making. Integrated Assessment is an analytical process for treating the full causal system of
relationships among policies, human systems, and environmental processes. Integrated assessments ensure that interactions between
human behavior and environmental change are taken into account appropriately and that the full implications of policies are evaluated. Integrated
assessment of health and environmental hazards can also be used to analyze the value of various kinds of information for prioritizing policy-
Human health and ecological assessments may address a range of hazards. Hazards may be
characterized for exposures to one stressor from a single source, for example, or multiple stressors may
be considered simultaneously. The definition of specific end points also may not be straightforward.
Whereas some assessments estimate readily observed effects (e.g., death), others may be concerned
with intermediate end points such as higher rates of asthma attacks or reversible, but distinct, changes
in ecosystem function. Assessments play important roles in considering the significance of issues such
as the effects of toxic substances on human health and ecosystems, of biodiversity loss on ecosystem
integrity, and of global change on human health and ecosystem function. Of particular importance is
the development of means for effective translation and conveyance of scientific knowledge gained
from research and providing a forum for involving policymakers in efficiently and effectively
understanding the implications of alternative policy options.
The Administration's goal is to use assessment methods to characterize, prevent, and reduce health and environmental hazards
in the most effective, efficient, and fair manner. Assessments should enhance dialogues about environmental threats between scientists,
managers, or policymakers and the public by effectively characterizing the potential costs of over- and under-regulation, as well as
the natures and magnitudes of uncertainties and assumptions.
The Administration is committed to strengthening the methods used to perform assessments, and the CENR has developed a set
of principles to guide federal agencies. These principles are broad and are intended to be applied flexibly because how particular
assessments are conducted will depend on factors such as their purpose, scope, audience, and timeframe.
Objectives for Developing Science Policy Tools
Ensure consistency in assessment methods, where appropriate.
Determine how social, cultural, and ecological concerns can be integrated into assessments.
Define criteria for framing and determining when to undertake an assessment, considering data needs, relevance to policy,
and required level of precision.
Identify the most appropriate geographic and temporal scales for assessing different environmental problems, particularly with
regard to policy needs.
Integrate social science research into environmental assessments.
Develop assessment methodologies for a range of endpoints and applications including natural hazards, toxic chemicals,
and natural resource development.
Assess for both humans and ecological systems variations in physiological susceptibilities of different populations and
effects on especially vulnerable populations (e.g., children).
Evaluate the impacts of, or exposures to, multiple and/or cumulative chemical, biological, and/or physical stressors to
highly impacted resources or populations (e.g., workers).
Establish methods for hazard characterization that effectively translate and communicate scientific knowledge and its
Develop methods for appropriately using assessments to establish management priorities.
Key Policy Objectives
The greatest challenge facing decision makers today appears to be integrating information on different sorts of environmental threats into
decisions about the most effective and efficient allocation of resources. Hazards vary not only in their source or cause (e.g., the use of hazardous
chemicals, natural hazards, technological failures) but also in the types of end points they produce, in their scales (both temporally and
spatially), and in their distributions across space and time. Assessments may provide a means to organize and compare information about risks
associated with very different activities or sources and very different end points. Different types of data, both in their units of measurement
and in their availability and reliability, may also be aggregated and/or compared.
The assessment process is integral to decision making through integration of the understanding of the relevant sciences, socioeconomics, and policy necessary for better decisions. Criteria can be developed
to define when an assessment might improve policy decisions and for framing and bounding assessments so they are most appropriate and effective for policy decisions.
Principles for Environmental Assessments
Be comprehensive. Assessments should provide decision makers with summaries of current
scientific and socioeconomic understanding of changes to the environment and provide a
foundation for decisions about potential policy or management strategies.
Consider both natural and human-induced changes. Environmental change and potential
ecological and economic impacts should be placed in the context of changes that are a natural
part of the system's fluctuations.
Begin with a broad range of inputs. Assessments should include a wide range of information
about potential impacts, mitigation options, and adaptation strategies.
Summarize concisely the state of knowledge. Assessments should critically evaluate the range
of studies on an issue and reach as much consensus as possible. Assessments should be a
common reference point for decision makers, in contrast to sporadic and separate statements
reflecting the opinions of individuals.
Discuss uncertainty. Assessments should discuss what is known and unknown and address both
the majority and minority views on technical issues. Time frames for reducing uncertainty
should be estimated, if possible.
Undergo peer review. Assessments should be peer reviewed by the expert community. Several
dozen to several hundred reviewers may be involved in reviewing work over the course of an
Include stakeholder input. Stakeholders must be involved in the preparation and review of all
Support international activities. Assessments should support U.S. participation in the
preparation and review of international assessment activities related to environmental change.
Develop assessment tools. The assessment process should further the development of policy-
relevant assessment tools such as integrated assessment models and risk assessment.
Establish R&D priorities. Assessments should clarify near- and long-term science and policy
questions and help prioritize the research necessary to be responsive to policy issues.
Areas of Enhanced Emphasis
Ongoing and future research strategies must focus on strengthening the methods and models used for
assessments, as well as continuing to build the foundations of scientific data upon which they are
based. There is a growing recognition, for example, that exposure to environmental contaminants may
cause a variety of noncancer health effects such as reproductive, developmental, immunological, and
neurological effects, as well as a broad array of adverse ecological impacts.
Methods for integrated assessments. Methods will be developed further to integrate social and
economic considerations into assessments of environmental threats. Such research includes
establishing a stronger base of understanding about human processes and how they influence (and
are influenced by) environmental change, developing generally accepted procedures for eliciting
both market and nonmarket values of environmental goods and services, and evaluating the
efficacy of various policy options to manage the environment and natural resources.
Risk characterization and communication. Research will be emphasized to develop and improve
methods for the characterization of risks and the effective transfer of scientific information about
risks and their attendant uncertainties to decision makers. Current policy controversies include calls
for greater transparency of regulatory risk assessments. Critics are concerned that federal agencies
do not always use the best scientific information and methods available, that agencies are not
explicit in how they weigh other social and environmental considerations, and that risk assessment
methods are not consistent across, or even within, agencies.
Criteria and indicators for ecosystem health. Important research aims to identify criteria and
indicators for ecological health that are compatible with broad policy goals including protecting
environmental health and ecosystem biodiversity. These criteria and indicators should be amenable
to measurement and reflect structural and functional interrelationships within ecosystems.
Indicators of adverse ecological effects should be integrated in framing assessments and defining
relevant data needs and should assist in considering how ecological risks ought to be incorporated
consistently into policy decisions. Such research should also guide monitoring efforts to identify
and assess ecological disruptions that may be linked to changing environmental conditions.
Human and ecological exposure. Research on multiple and/or cumulative exposures and
alternative pathways of exposure to hazardous pollutants, particularly for mixtures (both of
chemicals and physical stressors), will be enhanced. This research involves the natural and physical
sciences for characterizing mixtures and the biological sciences for understanding their effects.
Such research should also include studies on environmental fate, that is, how contaminants
disperse, react, persist, and/or accumulate. The social sciences provide a means to integrate
research about human activity into assessments, understanding individual and social perceptions
and responses that may influence risks or contribute to variations in exposure.
Mechanisms of disease and ecological impacts. Research will be continued to identify and predict
the magnitudes of new ecological risks and human health effects. Research on biological
mechanisms (both human and ecological) helps identify intermediate end points, set research and
testing priorities, develop biomarkers of diseases and exposures, and understand variations in
human susceptibilities to hazards. This research includes the investigations of pharmacokinetics,
metabolism, and biological fate.
Selected Milestones, 1995 - 1998
Complete the National Acid Precipitation Assessment Program (NAPAP) report to Congress, assessing the
(1) reduction in deposition rates necessary to prevent adverse ecological effects and (2) the costs, benefits,
and effectiveness of the current acid deposition control strategies mandated under Title IV of the 1990 Clean
Air Act Amendments (CAAA) (air quality).
Complete the Second Assessment of the Intergovernmental Panel on Climate Change (IPCC), a three-part
IPCC assessment summarizing scientific results from around the world on the effects of human activities on
climate. Initiate efforts to conduct regional and national assessments to identify vulnerabilities to climate
change and the benefits and costs of various response options for dealing with or responding to climate
change (global change).
Complete a plan for a national risk assessment to guide U.S. planning for natural disaster avoidance and
response through an understanding of the interactions between natural hazards and both natural and human
environments (natural hazard reduction).
Finalize the reassessment of dioxins and related compounds, evaluating health and ecological effects and
exposures. This reassessment has major implications because of the ubiquity of dioxins and their association
with adverse effects with very low levels of exposure (toxics).
Produce a state-of-the-science ozone assessment, a comprehensive statement about the current knowledge of
surface-ozone science, sponsored by relevant agencies, reviewed by peers and stakeholders, and timed to air
decisions associated with midcourse corrections in the state implementation plans required by the CAAA (air
Complete the report for the first 20 National Water Quality Assessment Program sites, and initiate detailed
planning for the final 20 sites (water resources).
Complete a peer-reviewed, comprehensive national assessment of the U.S. coastal environment that
integrates evaluations of the state of the natural environment with assessments of the effectiveness of current
governance mechanisms and structures and the social and economic effects of environmental change (water
resources and coastal and marine environments).
Complete an assessment of the atmospheric effects of stratospheric aircraft (global change).
Seek broad-based scientific consensus on select social and economic models for use in modeling of
environmental decisions, such as integrated assessments of climate change.
Develop improved methods for examining risk in complex and interdependent physical, engineering, and
social environments to design more effective risk management systems.