A Multiattribute Utility Analysis of Alternative Sites for the Disposal of Nuclear Waste

Five potential sites nominated for the Nation's first geologic repository for disposing of nuclear waste are evaluated using multiattribute utility analysis. The analysis was designed to aid the Department of Energy in its selection of 3 sites for characterization, a detailed data-gathering process that will involve the construction of exploratory shafts for underground testing and that may cost as much as $1 billion per site. The analysis produced insights into the relative advantages and disadvantages of the nominated sites and clarified current uncertainties regarding repository performance.     

Risk Analysis and Risk Management: An Historical Perspective

This paper reviews the history of risk analysis and risk management, giving special emphasis to the neglected period prior to the 20th century. The overall objective of the paper is to: (1) dampen the prevailing tendency to view present-day concerns about risk in an ahistorical context; (2) shed light on the intellectual antecedents of current thinking about risk; (3) clarify how contemporary ideas about risk analysis and societal risk management differ significantly from the past; and (4) provide a basis for anticipating future directions in risk analysis and management.     

A New Multicriteria Risk Mapping Approach Based on a Multiattribute Frontier Concept

Invasive species risk maps provide broad guidance on where to allocate resources for pest monitoring and regulation, but they often present individual risk components (such as climatic suitability, host abundance, or introduction potential) as independent entities. These independent risk components are integrated using various multicriteria analysis techniques that typically require prior knowledge of the risk components’ importance. Such information is often nonexistent for many invasive pests. This study proposes a new approach for building integrated risk maps using the principle of a multiattribute efficient frontier and analyzing the partial order of elements of a risk map as distributed in multidimensional criteria space. The integrated risks are estimated as subsequent multiattribute frontiers in dimensions of individual risk criteria. We demonstrate the approach with the example of Agrilus biguttatus Fabricius, a high‐risk pest that may threaten North American oak forests in the near future. Drawing on U.S. and Canadian data, we compare the performance of the multiattribute ranking against a multicriteria linear weighted averaging technique in the presence of uncertainties, using the concept of robustness from info‐gap decision theory. The results show major geographic hotspots where the consideration of tradeoffs between multiple risk components changes integrated risk rankings. Both methods delineate similar geographical regions of high and low risks. Overall, aggregation based on a delineation of multiattribute efficient frontiers can be a useful tool to prioritize risks for anticipated invasive pests, which usually have an extremely poor prior knowledge base.     

基于知识元的突发事件风险分析

科学地分析突发事件的风险,有利于应急管理部门正确制定应对方案,降低事件损失。突发事件风险分析中受到多因素高维数据和小样本数据信息不完备的约束,无法全面识别突发事件的风险。本文从突发事件系统观点出发,以知识元模型、投影寻踪方法和信息扩散理论为基础,提出了基于知识元的突发事件风险分析方法。该方法采用知识元模型描述了突发事件已认知的共性本体特征,通过探寻事件风险等级标准数据的最佳投影方向降低了输入元素观测数据的维数,将输入元素观测样本所包含的风险信息扩散到输出属性的风险指标论域的控制点上,从而确定了突发事件发生的风险概率。实例分析中,根据国家《地表水环境质量标准（GB3838-2002）》划分水污染风险等级,利用某湖泊8个监测点实时检测数据,分析该湖泊突发水污染事件的风险性。研究结果表明基于知识元的突发事件风险分析方法能够根据研究区域突发事件风险等级标准和观测点的样本数据,动态定量的分析和评估突发事件潜在风险,为突发事件的应急管理提供科学依据。本文提出的突发事件风险方法对于已经建立实时监测系统的危险区域分析突发事件的风险性具有一定的借鉴意义。     

Decision Making Under Uncertainty—An Example for Seismic Risk Management

Decision-making techniques are used to select the "best" alternatives under multiple and often conflicting criteria. Multicriteria decision making (MCDM) necessitates to incorporate uncertainties in the decision-making process. The major thrust of this article is to extend the framework proposed by Yager^{( 1 )} for multiple decisionmakers and fuzzy utilities (payoffs). In addition, the concept of expert credibility factor is introduced. The proposed approach is demonstrated for an example of seismic risk management using a heuristic hierarchical structure. A step-by-step formulation of the proposed approach is illustrated using a hypothetical example and a three-story reinforced concrete building.     

Risk-Adjusted Mission Value: Trading Off Mission Risk for Mission Value

This article develops a decision-theoretic methodology for the risk-adjusted mission value (RAMV) for selecting between alternative missions in the presence of uncertainty in the outcomes of the missions. This methodology permits trading off mission risk for mission value, something that probabilistic risk analysis cannot do unless it explicitly incorporates both mission value and risk aversion of the project management. The methodology, in its complete implementation, is consistent with the decision theory known as expected utility theory, although it differs from conventional decision theory in that the probabilities and all but one of the utilities are not those of the decision maker. The article also introduces a new interpretation of risk aversion. The methodology is consistent with the elementary management concept concerning division of labor. An example is presented for selecting between discrete alternatives-four landing sites on Mars. A second example is presented for selecting among a set of continuous alternatives-a comet flyby distance. The methodology is developed within the context of scientific missions, but the methodology is equally applicable to any situation requiring outcome value judgments, probability judgments, and risk aversion judgments by different constituencies.     

What Can Decision Analysis Do for Invasive Species Management?

Decisions about management of invasive species are difficult for all the reasons typically addressed by multiattribute decision analysis: uncertain outcomes, multiple and conflicting objectives, and many interested parties with differing views on both facts and values. This article illustrates how the tools of multiattribute analysis can improve management of invasive species, with an emphasis on making explicit the social values and preferences that must inform invasive species management. Risk assessment protocols developed previously for invasive species management typically suffer from two interacting flaws: (1) separating risk assessment from risk management, thus disrupting essential connections between the social values at stake in invasive species decisions and the scientific knowledge necessary to predict the likely impacts of management actions, and (2) relying on expert judgment about risk framed in qualitative and value-laden terms, inadvertently mixing the expert's judgment about what is likely to happen with personal preferences. Using the values structuring and probability-modeling elements of formal decision analysis can remedy these difficulties and make invasive species management responsive to both good science and public values. The management of feral pigs in Hawaiian ecosystems illustrates the need for such an integrated approach.     

A Review of the High-Level Nuclear Waste Repository Siting Analysis

We critique two 1986 Department of Energy reports concerning the selection of sites for characterization as the nation's first high-level nuclear waste repository. We find that the multiattribute utility analysis of the five nominated sites was well done, although we express concern about the assessed probabilities, question the construction of two important attribute scales, and disagree with some of the value tradeoffs that were used. In contrast, we find the logic of the recommendations report to be weak and unconvincing.     

Uncertainties in Nuclear Probabilistic Risk Analyses

There are many uncertainties in a probabilistic risk analysis (PRA). We identify the different types of uncertainties and describe their implications. We then summarize the uncertainty analyses which have performed in current PRAs and characterize results which have been obtained. We draw conclusions regarding interpretations of uncertainties, areas having largest uncertainties, and needs which exist in uncertainty analysis. We finally characterize the robustness of various utilizations of PRA results.     

Attitudes and Risk Perceptions of Stakeholders in a Nuclear Waste Siting Issue

Stakeholders are often regarded as a critically important group in such issues as the siting of nuclear facilities. In this article, stakeholders were identified on the basis of self-reported activities with regard to a nuclear waste siting issue under debate in four communities. Data were obtained in an extensive mailed survey from a total of 2,548 respondents, approximately an equal number from each community. The overall response rate was 43.9%. Some of the results and telephone interviews with a sample of the nonrespondents indicated that the data are reasonably representative of the respective populations. Stakeholder activities were measured by 20 questions and combined with an index of stakeholder activity level, dichotomized at the 90th percentile. Stakeholders were found to have a higher level of education than others, but otherwise they did not differ in demographics. They did not tend to see risks in general as high, but were quite interested and involved in the nuclear waste siting issue. The stakeholder activity level correlated with risk perception and attitudes in the waste siting issue, but with different signs for those who were for and those who were opposed: stakeholders of both types had more extreme views than others, but in different directions. In addition, stakeholder opponents were much more likely to strongly espouse extreme statements regarding the project than were supporters who also were stakeholders. Implications for risk management and communication are discussed.     

Variability and Uncertainty Meet Risk Management and Risk Communication

In the past decade, the use of probabilistic risk analysis techniques to quantitatively address variability and uncertainty in risks increased in popularity as recommended by the 1994 National Research Council that wrote Science and Judgment in Risk Assessment. Under the 1996 Food Quality Protection Act, for example, the U.S. EPA supported the development of tools that produce distributions of risk demonstrating the variability and/or uncertainty in the results. This paradigm shift away from the use of point estimates creates new challenges for risk managers, who now struggle with decisions about how to use distributions in decision making. The challenges for risk communication, however, have only been minimally explored. This presentation uses the case studies of variability in the risks of dying on the ground from a crashing airplane and from the deployment of motor vehicle airbags to demonstrate how better characterization of variability and uncertainty in the risk assessment lead to better risk communication. Analogies to food safety and environmental risks are also discussed. This presentation demonstrates that probabilistic risk assessment has an impact on both risk management and risk communication, and highlights remaining research issues associated with using improved sensitivity and uncertainty analyses in risk assessment.     

Emergency and Disaster: Pervasive Risk and Public Bureaucracy in Developing Nations

Developing nations experience pervasive risk of devastation, human and property loss resulting from human and natural disasters. This level of risk is attributable to socioeconomic stress, aging and inadequate physical infrastructure, weak education and preparedness for disaster and insufficient fiscal and economic resources to carefully implement the preparedness, response, mitigation and recovery components of integrated emergency management. This article examines these dynamics using a conceptual framework derived from chaos theory and emergency management theory and raises several critical methodological issues related to inquiries into disaster and emergency management dynamics in developing nations.     

Nuclear Risk Management on Stage: A Decision Analysis Perspective on the UK's Committee on Radioactive Waste Management

In 2003, the UK government set up a broad-based Committee on radioactive waste management (CoRWM) to look at the UK's policy on radioactive waste management with a view to jumpstarting a stalled policy process. The committee's brief was to come up with a set of recommendations that would protect the public and the environment, and be capable of inspiring public confidence. After consulting widely with the public and stakeholders, and drawing on advice from scientists and other experts, CoRWM arrived at a remarkably well-received set of recommendations. On the basis of our experiences of working on CoRWM's multi-criteria decision analysis of different management options, study of CoRWM documentation, and interviews with committee members, we describe the explicit and implicit principles that guided CoRWM. We also give an account of the process by which CoRWM arrived at its conclusions, covering four phases: framing, shortlisting, option assessment, and integration; and four cross-cutting activities: public and stakeholder engagement (PSE), science and engineering input, ethics and social science input, and learning from overseas practice. We finish by outlining some of the key developments in the UK's radioactive waste management process, which followed on from the publication of CoRWM's report, and present our reflections for the benefit of the risk and decision analysts of future committees that, like CoRWM, are charged with recommending to government on the management of technically complex and risky technologies, drawing on extensive public and stakeholder consultation.     

Intelligent Adversary Risk Analysis: A Bioterrorism Risk Management Model

The tragic events of 9/11 and the concerns about the potential for a terrorist or hostile state attack with weapons of mass destruction have led to an increased emphasis on risk analysis for homeland security. Uncertain hazards (natural and engineering) have been successfully analyzed using probabilistic risk analysis (PRA). Unlike uncertain hazards, terrorists and hostile states are intelligent adversaries who can observe our vulnerabilities and dynamically adapt their plans and actions to achieve their objectives. This article compares uncertain hazard risk analysis with intelligent adversary risk analysis, describes the intelligent adversary risk analysis challenges, and presents a probabilistic defender–attacker–defender model to evaluate the baseline risk and the potential risk reduction provided by defender investments. The model includes defender decisions prior to an attack; attacker decisions during the attack; defender actions after an attack; and the uncertainties of attack implementation, detection, and consequences. The risk management model is demonstrated with an illustrative bioterrorism problem with notional data.     

Quantifying Uncertainty in a Risk Assessment Using Human Data

A call for risk assessment approaches that better characterize and quantify uncertainty has been made by the scientific and regulatory community. This paper responds to that call by demonstrating a distributional approach that draws upon human data to derive potency estimates and to identify and quantify important sources of uncertainty. The approach is rooted in the science of decision analysis and employs an influence diagram, a decision tree, probabilistic weights, and a distribution of point estimates of carcinogenic potency. Its results estimate the likelihood of different carcinogenic risks (potencies) for a chemical under a specific scenario. For this exercise, human data on formaldehyde were employed to demonstrate the approach. Sensitivity analyses were performed to determine the relative impact of specific levels and alternatives on the potency distribution. The resulting potency estimates are compared with the results of an exercise using animal data on formaldehyde. The paper demonstrates that distributional risk assessment is readily adapted to situations in which epidemiologic data serve as the basis for potency estimates. Strengths and weaknesses of the distributional approach are discussed. Areas for further application and research are recommended.     

An Analysis of the de minimis Strategy for Risk Management

A de minimis risk management strategy sets a threshold so that risks below the specified level are defined as trivial and exempted from further consideration. The intended purpose is to help avoid inappropriate and wasteful concern with insignificant low-level risks. In most instances a de minimis strategy is likely to have beneficial or innocuous effects, but under certain circumstances large differences may develop between nominal and actual de minimis levels. The potential for such discrepancies illustrates why de minimis (and all other risk management) strategies should be evaluated on the basis of the portfolio of risks that would accumulate from applying such strategies over time, rather than on the apparent reasonableness of any single instance of application.     

Cellular Automata‐Based Systematic Risk Analysis Approach for Emergency Response

Emergency response is directly related to the allocation of emergency rescue resources. Efficient emergency response can reduce loss of life and property, limit damage from the primary impact, and minimize damage from derivative impacts. An appropriate risk analysis approach in the event of accidents is one rational way to assist emergency response. In this article, a cellular automata‐based systematic approach for conducting risk analysis in emergency response is presented. Three general rules, i.e., diffusive effect, transporting effect, and dissipative effect, are developed to implement cellular automata transition function. The approach takes multiple social factors such as population density and population sensitivity into consideration and it also considers risk of domino accidents that are increasing due to increasing congestion in industrial complexes of a city and increasing density of human population. In addition, two risk indices, i.e., individual risk and aggregated weighted risk, are proposed to assist decision making for emergency managers during emergency response. Individual risk can be useful to plan evacuation strategies, while aggregated weighted risk can help emergency managers to allocate rescue resources rationally according to the degree of danger in each vulnerable area and optimize emergency response programs.