Development and Consideration of Global Policies for Managing the Future Risks of Poliovirus Outbreaks: Insights and Lessons Learned Through Modeling

The success of the Global Polio Eradication Initiative promises to bring large benefits, including sustained improvements in quality of life (i.e., cases of paralytic disease and deaths avoided) and costs saved from cessation of vaccination. Obtaining and maintaining these benefits requires that policymakers manage the transition from the current massive use of oral poliovirus vaccine (OPV) to a world without OPV and free of the risks of potential future reintroductions of live polioviruses. This article describes the analytical journey that began in 2001 with a retrospective case study on polio risk management and led to development of dynamic integrated risk, economic, and decision analysis tools to inform global policies for managing the risks of polio. This analytical journey has provided several key insights and lessons learned that will be useful to future analysts involved in similar complex decision-making processes.     

论信贷风险担保的性质与功能

西方发达市场经济国家或地区的经济发展表明，信贷风险的担保机制对金融信贷质量提高与宏观金融稳定具有非常重要的决定作用。然而我国对信贷风险担保不仅在理论研究上是空白，而且在实践上也很少应用，因此，我国的信贷质量低下。本文在充分剖析了信贷风险担保的性质与功能的基础上，揭示了我国推广应用信贷风险担保机制的客观必然性。     

Estimating the association parameter for copula models under dependent censoring

Summary. Many biomedical studies involve the analysis of multiple events. The dependence between the times to these end points is often of scientific interest. We investigate a situation when one end point is subject to censoring by the other. The model assumptions of Day and co-workers and Fine and co-workers are extended to more general structures where the level of association may vary with time. Two types of estimating function are proposed. Asymptotic properties of the proposed estimators are derived. Their finite sample performance is studied via simulations. The inference procedures are applied to two real data sets for illustration.     

A Hint of Risk: Tradeoffs Between Quantitative and Qualitative Risk Factors

Risk-perception research plays an active role in discussions of risk-management alternatives. However, little guidance is provided regarding how public concerns should be weighed against other sources of cost and benefits. This paper reports the results of two experiments that measure tradeoffs among cost (in dollars), a quantitative risk measure (number of deaths or injuries), and several qualitative characteristics associated with perceived risk. Most subjects were willing to make the requested trade. However, the perceived risk information led others to reject the proposed technology.     

Measures of Compounding Conservatism in Probabilistic Risk Assessment

Concern about the degree of uncertainty and potential conservatism in deterministic point estimates of risk has prompted researchers to turn increasingly to probabilistic methods for risk assessment. With Monte Carlo simulation techniques, distributions of risk reflecting uncertainty and/or variability are generated as an alternative. In this paper the compounding of conservatism⁽¹⁾ between the level associated with point estimate inputs selected from probability distributions and the level associated with the deterministic value of risk calculated using these inputs is explored. Two measures of compounded conservatism are compared and contrasted. The first measure considered, F , is defined as the ratio of the risk value, R _d, calculated deterministically as a function of n inputs each at the j th percentile of its probability distribution, and the risk value, R _j that falls at the j th percentile of the simulated risk distribution (i.e., F=R_d/R_j). The percentile of the simulated risk distribution which corresponds to the deterministic value, R_d , serves as a second measure of compounded conservatism. Analytical results for simple products of lognormal distributions are presented. In addition, a numerical treatment of several complex cases is presented using five simulation analyses from the literature to illustrate. Overall, there are cases in which conservatism compounds dramatically for deterministic point estimates of risk constructed from upper percentiles of input parameters, as well as those for which the effect is less notable. The analytical and numerical techniques discussed are intended to help analysts explore the factors that influence the magnitude of compounding conservatism in specific cases.     

Evaluating Risk Communications: Completing and Correcting Mental Models of Hazardous Processes, Part II

We propose a decision-analytic framework, called the mental models approach , for evaluating the impact of risk communications. It employs multiple evaluation methods, including think-aloud protocol analysis, problem solving, and a true-false test that allows respondents to express uncertainty about their answers. The approach is illustrated in empirical comparisons of three brochures about indoor radon.     

Stigma Happens: Social Problems in the Siting of Nuclear Waste Facilities

The paper by Metz challenges the view that stigma associated with a nuclear waste repository might lead to significant economic losses to the host region. We have been invited to comment on the general issues raised by this paper. We find that much of the evidence presented in the paper consists of factual and conceptual errors and misrepresentations of the research literature. Based on our review of evidence documenting the social and economic impacts of perceived risk, we conclude that stigma is an important phenomenon that is symptomatic of fundamental problems with the way in which nuclear waste facilities are sited.     

对承租人的信用风险评估及防范

在金融租赁机构所面临的风险中 ,我国目前最大的风险是信用风险。通过确定承租人的信用分数、评定承租人信用等级、确定其风险系数等方法 ,对承租人的信用风险进行评估。在评估基础上 ,应采取根据风险系数 ,选择承租人、对风险系数进行修正、重视租赁合同、租中进行检查等措施防范风险     

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.     

A Further Examination of Cumulative Prospect Theory Parameterizations

Recent experimental studies have focused on fitting parameterized functional forms to cumulative prospect theory's weighting function. This paper examines the behavioral implications of the functional forms and the estimated parameters. We find that none of the parameterizations can simultaneously account for gambling on unlikely gains and the Allais paradox behavior or other strong choice patterns from experiments. Parameter estimates that lead to reasonable amounts of insurance and gambling behavior tend to also generate large risk premia. Taken as a whole, the analysis suggests that the functional forms proposed in the literature are not suitable for generalization to applied settings.