Modeling Finite‐Time Failure Probabilities in Risk Analysis Applications

In this article, we introduce a framework for analyzing the risk of systems failure based on estimating the failure probability. The latter is defined as the probability that a certain risk process, characterizing the operations of a system, reaches a possibly time‐dependent critical risk level within a finite‐time interval. Under general assumptions, we define two dually connected models for the risk process and derive explicit expressions for the failure probability and also the joint probability of the time of the occurrence of failure and the excess of the risk process over the risk level. We illustrate how these probabilistic models and results can be successfully applied in several important areas of risk analysis, among which are systems reliability, inventory management, flood control via dam management, infectious disease spread, and financial insolvency. Numerical illustrations are also presented.     

Risk factors for severe perineal trauma during vaginal childbirth: A Western Australian retrospective cohort study

AimTo determine rates and risk factors for third and fourth degree perineal tears (severe perineal trauma) in a Western Australian context.Design and settingA retrospective hospital-based cohort study was performed using computerised data for 10,408 singleton vaginal deliveries from 28 weeks gestation.MethodsWomen with severe perineal trauma were compared to those without. Logistic regression analysis, stratified by parity, was used to assess demographic and obstetric factors associated with perineal trauma.ResultsSevere perineal trauma incidence was 3% (338/10408), 5.4% (239/4405) for primiparas and 1.7% (99/5990) for multiparas (p < 0.001). Adjusted risk factors associated with trauma and common across parity included Asian or Indian ethnicity, shoulder dystocia and assisted delivery. Epidural analgesia (OR 0.72, 95% CI 0.54–0.96), preterm birth (OR 0.40, 95% CI 0.23–0.72) and episiotomy (OR 0.54, 95% CI 0.39–0.74) were protective in primiparas, while episiotomy was associated with increased risk in multiparas (OR 2.01, 95% CI 1.18–3.45). Additional factors among primiparas were occipito posterior (OP) delivery (OR 3.35, 95% CI 1.75–6.41) and prolonged second stage (OR 1.98, 95% CI 1.46–2.68), and among multiparas included gestational diabetes (OR 1.78, 95% CI 1.04–3.03) and birth weight >4000 g (OR 1.86, 95% CI 1.10–3.15).ConclusionParity differences in risk factors such as episiotomy, infant weight, OP delivery, gestational diabetes and prolonged second stage warrant investigation into clinical management. Although rates differ internationally, and replication evidence has confirmed consistency for certain demographic and obstetric factors, the development of internationally endorsed clinical guidelines and further research around interventions to protect the perineum are recommended.     

Evaluation of Inhaled Versus Deposited Dose Using the Exponential Dose‐Response Model for Inhalational Anthrax in Nonhuman Primate,Rabbit, and Guinea Pig

The application of the exponential model is extended by the inclusion of new nonhuman primate (NHP), rabbit, and guinea pig dose‐lethality data for inhalation anthrax. Because deposition is a critical step in the initiation of inhalation anthrax, inhaled doses may not provide the most accurate cross‐species comparison. For this reason, species‐specific deposition factors were derived to translate inhaled dose to deposited dose. Four NHP, three rabbit, and two guinea pig data sets were utilized. Results from species‐specific pooling analysis suggested all four NHP data sets could be pooled into a single NHP data set, which was also true for the rabbit and guinea pig data sets. The three species‐specific pooled data sets could not be combined into a single generic mammalian data set. For inhaled dose, NHPs were the most sensitive (relative lowest LD₅₀) species and rabbits the least. Improved inhaled LD₅₀s proposed for use in risk assessment are 50,600, 102,600, and 70,800 inhaled spores for NHP, rabbit, and guinea pig, respectively. Lung deposition factors were estimated for each species using published deposition data from Bacillus spore exposures, particle deposition studies, and computer modeling. Deposition was estimated at 22%, 9%, and 30% of the inhaled dose for NHP, rabbit, and guinea pig, respectively. When the inhaled dose was adjusted to reflect deposited dose, the rabbit animal model appears the most sensitive with the guinea pig the least sensitive species.     

The Relative Weights of Direct and Indirect Experiences in the Formation of Environmental Risk Beliefs

Direct experiences, we find, influence environmental risk beliefs more than the indirect experiences derived from outcomes to others. This disparity could have a rational basis. Or it could be based on behavioral proclivities in accord with the well‐established availability heuristic or the vested‐interest heuristic, which we introduce in this article. Using original data from a large, nationally representative sample, this article examines the perception of, and responses to, morbidity risks from tap water. Direct experiences have a stronger and more consistent effect on different measures of risk belief. Direct experiences also boost the precautionary response of drinking bottled water and drinking filtered water, while indirect experiences do not. These results are consistent with the hypothesized neglect of indirect experiences in other risk contexts, such as climate change.     

Risk Analysis for U.S. Offshore Wind Farms: The Need for an Integrated Approach

Wind power is becoming an increasingly important part of the global energy portfolio, and there is growing interest in developing offshore wind farms in the United States to better utilize this resource. Wind farms have certain environmental benefits, notably near‐zero emissions of greenhouse gases, particulates, and other contaminants of concern. However, there are significant challenges ahead in achieving large‐scale integration of wind power in the United States, particularly offshore wind. Environmental impacts from wind farms are a concern, and these are subject to a number of on‐going studies focused on risks to the environment. However, once a wind farm is built, the farm itself will face a number of risks from a variety of hazards, and managing these risks is critical to the ultimate achievement of long‐term reductions in pollutant emissions from clean energy sources such as wind. No integrated framework currently exists for assessing risks to offshore wind farms in the United States, which poses a challenge for wind farm risk management. In this “Perspective”, we provide an overview of the risks faced by an offshore wind farm, argue that an integrated framework is needed, and give a preliminary starting point for such a framework to illustrate what it might look like. This is not a final framework; substantial work remains. Our intention here is to highlight the research need in this area in the hope of spurring additional research about the risks to wind farms to complement the substantial amount of on‐going research on the risks from wind farms.     

Transparency in Europe: A Quantitative Study

In recent years, European pharmaceutical regulators have increasingly committed to heightening access to raw safety‐related data as part of a wave of transparency initiatives (e.g., providing public Internet‐mediated access to clinical trials data). Yet, the regulators—who are under significant pressure—have not yet benefited from a systematic review of this new policy. In seeking to inject much needed evidence, this article explores the effects of new transparency policies designed to promote meaningful communication of risks and benefits to patients. Results of a cross‐national European survey with respondents from Great Britain, the Netherlands, Spain, France, Germany, and Sweden (N = 5,648) shed light on how patients and the public are likely to react to the regulators’ new transparency policies. The findings demonstrate clear national variations in how European citizens are likely to react and emphasize the need to develop evidence‐based, reasoned transparency policies that integrate benefit‐risk communication. The authors conclude by providing six specific recommendations, informed by the study, that seek to improve the European transparency model both within the medical field and across health, safety, and environmental policy domains.     

Portfolio Analysis of Layered Security Measures

Layered defenses are necessary for protecting the public from terrorist attacks. Designing a system of such defensive measures requires consideration of the interaction of these countermeasures. In this article, we present an analysis of a layered security system within the lower Manhattan area. It shows how portfolios of security measures can be evaluated through portfolio decision analysis. Consideration is given to the total benefits and costs of the system. Portfolio diagrams are created that help communicate alternatives among stakeholders who have differing views on the tradeoffs between security and economic activity.     

Has Successful Terror Gone to Ground?

This article considers all 87 attacks worldwide against air and rail transport systems that killed at least two passengers over the 30‐year period of 1982–2011. The data offer strong and statistically significant evidence that successful acts of terror have “gone to ground” in recent years: attacks against aviation were concentrated early in the three decades studied whereas those against rail were concentrated later. Recent data are used to make estimates of absolute and comparative risk for frequent flyers and subway/rail commuters. Point estimates in the “status quo” case imply that mortality risk from successful acts of terror was very low on both modes of transportation and that, whereas risk per trip is higher for air travelers than subway/rail commuters, the rail commuters experience greater risk per year than the frequent flyers.     

Paradoxes of risk management: Social responsibility and self-exclusion in Dutch casinos

This article deals with the basic contradictions of risk management and responsibility regarding problem gambling and self-exclusions, and draws special attention to the role knowledge production and science play in the construction and evaluation of gambling risks. This remarkable case of corporate social responsibility (CSR) is analyzed from a risk-governance perspective. It is grounded on a case study of the CSR practice of the Dutch casino monopoly, in particular the problem gambling mitigation and self-exclusion program of this corporation. The intentions and operations of this ‘responsible gambling’ practice constitute new business values and working norms. At the same time empirical evaluations of the self-exclusion program reveal that despite all the efforts put in the risk-management strategies, a significant part of the problem cannot be addressed at all. This points toward a major paradox of risk management. Overall the article highlights the ambiguous nature of risk management and responsible gambling.     

Spatial Distribution of Flood Risk and Quality of Spatial Management: Case Study in Odra Valley,Poland

This article presents methodological solutions aimed at presenting the spatial distribution of flood risk and quality of spatial management (land use), indicating both those areas used reasonably and those requiring modification. The purpose was to identify key risk areas and risk‐free areas from the point of view of human security and activity on the floodplains, based on the examples of the vicinities of Wroclaw and Raciborz in the Odra Valley, Poland. Due to recent climate change, Poland has suffered the effects of severe flooding (e.g., 1997, 2001, 2010). The analyses conducted were motivated by the European Parliament and Council's recently implemented Directive 2007/60/WE, as well as by the demand for studies for local spatial planning. The analysis indicates that reasonably developed areas do not account for the majority of those studied, making up 36% of the Wroclaw area and 15% of the Raciborz area.