Comparative risk analysis is an environmental decision-making tool used to
systematically measure, compare, and rank environmental problems or issue areas.
The process typically focuses on the risks a problem poses to human
health, the natural environment and quality of life, and results in a list (or
lists) of issue areas ranked in terms of relative risks. Efforts to set environmental priorities raise a wide variety of questions - be sure to review Scorecard's Frequently Asked Questions about comparative risk.
WHAT IS THE GOAL OF COMPARATIVE RISK ANALYSIS?
Comparative risk analyses are undertaken to achieve numerous goals. The most
common goal is to establish priorities for a government agency, political body, or community at-large. It is often used to determine how to best
allocate limited resources for reducing or preventing environmental risks. Comparative risk analysis generally investigates "residual risks" -- the risks remaining after a problem is addressed by current regulatory controls. For example, a state may determine that its current drinking water quality efforts leave little residual risk to human health, relative to the higher level of residual health risk posed by criteria air pollutants. In this case,
comparative risk analysis suggests that future efforts should be directed at
reducing the risk associated with criteria air pollutants and not drinking
water quality.
Additionally, comparative risk analyses are often conducted to help spur
collaboration between government agencies, industry, interest groups and the
general public. Often, a comparative risk project will have a Public Advisory
Committee or Steering Committee comprised of representatives from numerous
stakeholder groups to help achieve this goal.
Along with priority-setting and increasing collaboration, comparative risk
projects also have education as one of the goals. The projects seek to educate both participating stakeholders and the general public about current environmental conditions and outstanding problems that need to be addressed in the future.
WHAT IS THE HISTORY OF COMPARATIVE RISK ANALYSIS?
Early efforts to protect the environment focused on adopting statutes that established regulatory programs to control pollution problems in separate media, such as the Clean Air Act or the Clean Water Act. However, it soon became apparent that most environmental problems are multi-media and could be more effectively addressed using a more integrated approach. During the mid 1980s, the US EPA sponsored a series of local Integrated Environmental Management Projects. These IEMPs were the first attempt to evaluate a range environmental threats and integrate media-specific risk assessment and risk management processes in order to set environmental priorities. Building upon these efforts, the US EPA conducted its first comparative risk project in 1987, Unfinished Business. In Unfinished Business, the US EPA compared and ranked 31 issues in terms of cancer risk, non-cancer risk, ecological risk, and welfare effects.
EPA's independent Science Advisory Board examined both the methods and findings of Unfinished Business in 1989 and 1990. The SAB gave its strong endorsement to the comparative risk approach to setting priorities in its report,
Reducing Risks: Setting Priorities and Strategies for Environmental Protection. The report concluded that the nation's environmental priorities were failing to address many of the most serious risks.
US EPA found the perspective offered by this initial priority setting project so helpful that it instructed all ten of its regions to conduct similar studies. Regional priority projects were completed by 1990, and the agency established a funding process to encourage similar projects at the state and local level. Since 1990, over 100 states, territories, counties,
cities and other local communities have conducted their own projects or are in
the process currently.
For more on the history of comparative risk assessment at EPA, see the National Academy of Public Administration's 1994 report on Setting Priorities, Getting Results. The Green Mountain Institute for Environmental Democracy's Directory of Comparative Risk Projects is the best online index of project status across the U.S.
LINKS TO USEFUL ONLINE RESOURCES FOR COMPARATIVE RISK ANALYSIS
For general information about how to conduct comparative risk analysis, see:
Green Mountain Institute's Resource Guide to Comparative Risk
U.S. EPA's Guidebook to Comparing Risks and Setting Environmental Priorities
For information about completed projects and the policy and technical issues involved in comparative risk, see:
Green Mountain Institute for Environmental Democracy's Comparative Risk Information On-line
Western Center for Environmental Decision-Making's Comparative Risk Comparative Risk Publications
For current information about the status of regional, state and local efforts to set environmental priorities, see:
U.S. EPA's Regional/State/Tribal Planning Homepage
