Individual Risk Criteria Research Articles

A multifactorial risk index for evaluation of anesthetic risk in dogs: the LeiV-Risk-Index

The Leipzig Veterinary Risk-Index - "LeiV-Risk-Index" is a multifactorial risk index developed to enable an improved objective assessment of the anesthetic risk in dogs. The scoring system is based on 10 risk factors affecting perioperative mortality. The aim of this study was to evaluate the applicability of the LeiV-Risk-Index and its risk factors as well as to perform a direct comparison with the ASA-classification. An online survey was conducted among veterinarians working in small animal medicine throughout Germany. Participants received a questionnaire containing information on 15 selected patients. They were asked to classify the patients according to the LeiV-Risk-Index and ASA-classification and to answer several questions concerning their professional background. The results were statistically analyzed considering the consistency among veterinarians of rating the different patients by using Fleiss'-Kappa. The correlation of LeiV-Risk-Index and ASA-classification was calculated. The consistency of all assigned LeiV-risk classes between participants was moderate (κ = 0.55) and higher than classification by ASA (κ = 0.33). On average, 3 different LeiV-risk classes and 4 different ASA-classes were assigned for one patient. There was a positive correlation between LeiV-risk class and increasing ASA-class. No effect of gender or clinical experience of the veterinarian could be demonstrated on ranking patients. There was also no effect of how confident veterinarians felt in applying the LeiV-Risk-Index. The LeiV-Risk-Index is the first index available in veterinary medicine for assessing anesthetic risk that is based on objective risk criteria and whose objectivity exceeds that of the ASA classification. Anesthetic patients can thus be evaluated more consistently in veterinary medicine as well. Utility and practicability were positively received by 95 % of the participants. Further revision of individual risk criteria needs to be reconsidered.

Determining Target Reliability Index of Structures Based on Cost Optimization and Acceptance Criteria for Fatality Risk

The target reliability index is pivotal to the design, assessment, inspection, and maintenance of structures. It is commonly determined by cost optimization. However, depending on the method of quantifying fatality cost, cost optimization may lead to inconsistent target reliability indices, causing inadequate or unnecessary investment for safety improvement. A new approach to determine the target reliability index is proposed by considering cost efficiency and human safety separately. In this approach, an optimal reliability index is determined through cost optimization, circumventing the quantification of fatality cost in failure consequences. The human safety requirement is fulfilled by adding a constraint to the cost optimization problem based on different acceptance criteria for fatality risk, including individual risk criteria, societal risk criteria, and marginal lifesaving cost principle. The reliability index associated with this constraint is termed herein as an acceptable reliability index. The target reliability index is determined as the maximum between the optimal and acceptable reliability indices. A parametric study is conducted to investigate the effects of various factors on the target reliability index, including the probability density distributions and uncertainties of structural demand as well as the number of potential fatalities.

Assessment of individual risk criteria for the disposal of radioactive waste

This article discusses the possibilities of determining the risk to individuals as a result of radiation exposure, which is one of the most common and important characteristics of environmental hazard. Environmental damage with the likelihood of an event contributing to the determination of environmental risk. In this case, the risk itself shows the effect of radiation on the human body. When determining the risk, it is necessary to take into account the power of an individual dose for a certain period of time. The criteria curves considered in the article take into account stochastic and non-stochastic effects. These criteria show compliance of waste disposal methods with requirements related to specific risk levels.

A Practical Method for the Evaluation of Societal Risk in the Context of the International Maritime Organization's Safety Level Approach

The Safety Level Approach (SLA) is a structured application of risk-based methodologies for the International Maritime Organization's (IMO's) rule-making process. When the SLA is applied, safety goals have to be provided. In order to set appropriate levels for safety goals, it is necessary to measure the tolerance degree of the current safety level. Based on the consistency with individual risk criteria and the principle of continuous improvement, this paper proposes an approach to establish the societal risk criteria, which can be used for setting safety goals in the context of the IMO's SLA. Furthermore, by defining dynamic factors to express risk aversion, a method for tolerance measurement of the current societal risk is developed. Finally, a case study into the societal risk evaluation of cruise ships and Roll-On Roll-Off (RO-RO) passenger ships is conducted.

Eligibility Criteria and Genetic Testing Results from a High-Risk Cohort for Hereditary Breast and Ovarian Cancer Syndrome in Southeastern Ontario

Germline mutations in breast and ovarian cancer are rare, with approximately 5% to 10% and 13% being hereditary in origin, respectively. In 2001, the Ontario Ministry of Health and Long Term Care, in an effort to contain costs, defined criteria to determine an individual's eligibility for BRCA genetic screening. We studied a cohort of individuals that have undergone genetic testing at Kingston General Hospital between 2001 and late 2013. We focused on determining whether the 13 risk criteria, defined by an expert working group for the Ontario Ministry of Health and Long Term Care, have performed according to expectations in this cohort. Our findings show that all of the criteria perform well by identifying carriers at the expected 10% rate defined by the guidelines. We demonstrate that loose application of the risk criteria does not further enrich for BRCA variant carriers. Our assessment of the established risk criteria that have been in use in Ontario for more than a decade, provide evidence for their effectiveness, and offer insights into how they may be expanded or improved.

Allocation of Individual Risk Criteria under LOPA Framework

Allocation of Individual Risk Criteria under LOPA Framework

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.

Risk tolerance criteria for layers of protection analysis

AbstractLayers of protection analysis (LOPA) facilitates risk‐informed decision making by allowing comparison of risk estimates with risk tolerance criteria to determine if the risk is tolerable. Various types of risk criteria exist, and it is essential that LOPA practitioners match the type of risks calculated with the type of criteria used to ensure that valid comparisons are made and sound decisions are taken. A common error is to use individual risk criteria but calculate societal risk measures, which can lead to more stringent risk reduction measures than needed. Correct use of risk tolerance criteria is especially important when LOPA is used to determine safety integrity levels for safety instrumented functions to comply with industry standards for safety instrumented systems when critical decisions on process safety are made. This article describes the type of risk criteria that should be used with LOPA and contrasts risk measures calculated with LOPA and quantitative risk analysis. The concept of a representative receptor is introduced to allow the calculation of individual risk measures as well as societal risk measures. © 2011 American Institute of Chemical Engineers Process Saf Prog, 2011

Target Reliability Levels for Design and Assessment of Onshore Natural Gas Pipelines

This paper proposes a set of reliability targets that can be used in the design and assessment of onshore natural gas pipelines. The targets were developed as part of a PRCI-sponsored project that aims to establish reliability-based methods as a viable alternative for pipeline design and assessment. The proposed targets are calibrated to meet risk levels that are considered widely acceptable. The proposed criteria are based on a detailed consideration of both societal and individual risk criteria. Two societal risk criteria were considered: the first based on a fixed expectation of the number of fatalities and the second based on a risk aversion function as characterized by a F/N relationship. Societal risk criteria were calibrated to match or exceed the average safety levels implied by current codes. Individual risk criteria were based on published tolerable levels. The target reliability levels corresponding to the three criteria are presented and a recommended set of targets is presented.

Reliability Based Design and Assessment for Location-Specific Failure Threats With Application to Natural Gas Pipelines

The acceptance criteria used in reliability based design and assessment are defined as a set of reliability targets (where reliability is defined as 1.0 minus the probability of failure). Because of the linear nature of pipeline systems, reliability targets are defined on a per kilometer-year basis. Such targets are directly applicable to failure causes (or limit states) that are equally likely to occur anywhere along a segment of the pipeline (e.g., equipment impact or yielding/rupture of defect-free pipe under internal pressure). They are, however, not directly applicable for design and assessment situations involving limit states that apply at known specific locations. Examples include design for geotechnical loads on a particular unstable slope or integrity assessment of a corrosion defect at a specific location (as determined by in-line inspection). In previous work, reliability targets for natural gas pipelines have been developed on the basis of appropriate societal and individual risk criteria. This paper describes an approach to adapt these targets and demonstrate compliance with them, for location-specific limit states. The approach is based on using separate checks to ensure that the individual and societal risk criteria underlying the targets are met. An example is included to demonstrate application of the approach to design a pipeline on an unstable slope.

Substratification of high-risk localised prostate cancer treated by radical prostatectomy

To evaluate the clinical outcome of high-risk prostate cancer (PC) treated by radical prostatectomy (RP) according to risk factors. Patients with stage cT1-T3 PC were stratified in high and low/intermediate risk groups using D'Amico's criteria: PSA>or=20 ng/ml or Gleason score>or=8 or clinical stage>or=T2c. The Kaplan Meier and Log rank test were used to generate estimates of biochemical free-survival (BFS) and PC specific mortality (PCSM). We analysed 1,109 patients with a median age of 64.1 years, a mean PSA of 12.8 and a median follow-up of 8.18 years (max. 17.5 years). Overall PSA failures (PSAF) were observed in 23.4%, mortality by all causes in 11.4% and PCSM in 2.9%. The 10-year BFS of the 290 high-risk was 45 versus 75.5% for low/intermediate risk patients and the 10-year PCSM was 10.3 versus 1.4%, respectively. Of the 290 high-risk PC, 25% had organ-confined disease at surgery with 28% PSAF compared to 55% PSAF for non-organ-confined PC irrespective of nodal status. High-risk patients with 1 or>or=2 high risk criteria had 2.6 and 3.86 times increased risk of PSAF compared to low/intermediate risk. Ten-year PCSM for PC individual risk criteria was 4.5% for PSA>or=20, 9.2% for stage>or=T2c and 18.2% for Gleason>or=8. Patients with high-risk PC treated by RP by experienced surgeons can have a favourable long-term survival. Further substratification should take into account the variable prognostic implication of the different individual risk factors.

Risk Criteria for the Shipping Industry

AbstractThis paper proposes dual risk criteria for the shipping industry based on a goal‐setting approach to safety requiring risk in the tolerability region to be as low as reasonably practicable (ALARP) within which there is a prescriptive target risk level which should not be reached. The prescriptive target risk level is intended for smaller companies satisfying the current safety and classification rules, while it is expected that leading companies would embrace the dynamic ALARP approach as a means for improving the current practice in a search for a better and more economical solution. Furthermore, it is shown that it is possible to formulate the societal risk criteria fully consistent with often legally imposed individual risk criteria. Copyright © 2006 John Wiley & Sons, Ltd.

Against "Individual Risk": A Sympathetic Critique of Risk Assessment

Individual currently plays a major role in risk assessment and in the regulatory practices of the health and safety agencies that employ risk assessment, such as EPA, FDA, OSHA, NRC, CPSC, and others. Risk assessors use the term to mean the number of deaths caused by some hazard. By contrast, is the incremental probability of death that the hazard imposes on some particular person. Regulatory decision procedures keyed to individual risk are widespread. This is true both for the regulation of toxic chemicals (the heartland of risk assessment), and for other health hazards, such as radiation and pathogens; and regulatory agencies are now beginning to employ individual risk criteria for evaluating safety threats, such as occupational injuries. Sometimes, agencies look to the risk imposed on the maximally exposed individual; in other contexts, the regulatory focus is on the average individual's risk, or perhaps the risk of a person incurring an above-average but nonmaximal exposure. Sometimes, agencies seek to regulate hazards so as to reduce the individual risk level (to the maximally exposed, high-end, or average individual) below 1 in 1 million. Sometimes, instead, a risk level of 1 in 100,000 or 1 in 10,000 or even 1 in 1000 is seen as de minimis. In short, the construct of individual risk plays a variety of decisional roles, but the construct itself is quite pervasive.This Article launches a systematic critique of agency decisionmaking keyed to individual risk. Part I unpacks the construct, and shows how it invokes a frequentist rather than Bayesian conception of probability. Part II surveys agency practice, describing the wide range of regulatory contexts where individual risk levels are wholly or partly determinative of agency choice: these include most of the EPA's major programs for regulating toxins (air pollutants under the Clean Air Act, water pollutants under the Clean Water Act and Safe Drinking Water Act, toxic waste dumps under the Superfund statute, hazardous wastes under RCRA, and pesticides under FIFRA) as well as the FDA's regulation of food safety, OSHA regulation of workplace health and safety risks, NRC licensing of nuclear reactors, and the CPSC's regulation of risky consumer products.In the remainder of the Article, I demonstrate that frequentist individual risk is a problematic basis for regulatory choice, across a range of moral views. Part III focuses on welfare consequentialism: the moral view underlying welfare economics and cost-benefit analysis. I argue that the sort of risk relevant to welfare consequentialism is Bayesian, not frequentist. Part IV explores the subtle, but crucial difference between frequentist and Bayesian risk. Part V moves beyond cost-benefit analysis and examines nonwelfarist moral views: specifically, safety-focused, deontological, contractualist, and democratic views. Here too, I suggest, regulatory reliance on frequentist individual risk should be seen as problematic. Part VI argues that current practices (as described at length in Part II) are doubly misguided: not only do they focus on frequentist rather than Bayesian risk, but they are also insensitive to population size.In short, the Article provides a wide ranging, critical analysis of contemporary risk assessment and risk regulation. The perspective offered here is that of the sympathetic critic. Risk assessment itself - the enterprise of quantifying health and safety threats - represents a great leap forward for public rationality, and should not be abandoned. Rather, the current conception of risk assessment needs to be reworked. Risk needs to be seen in Bayesian rather than frequentist terms. And regulatory choice procedures must be driven by population risk or some other measure of the seriousness of health and safety hazards that is sensitive to the size of the exposed population - not the risk that some particular person (whatever her place in the exposure distribution) incurs.

Against 'Individual Risk': A Sympathetic Critique of Risk Assessment

Individual currently plays a major role in risk assessment and in the regulatory practices of the health and safety agencies that employ risk assessment, such as EPA, FDA, OSHA, NRC, CPSC, and others. Risk assessors use the term to mean the number of deaths caused by some hazard. By contrast, is the incremental probability of death that the hazard imposes on some particular person. Regulatory decision procedures keyed to individual risk are widespread. This is true both for the regulation of toxic chemicals (the heartland of risk assessment), and for other health hazards, such as radiation and pathogens; and regulatory agencies are now beginning to employ individual risk criteria for evaluating safety threats, such as occupational injuries. Sometimes, agencies look to the risk imposed on the maximally exposed individual; in other contexts, the regulatory focus is on the average individual's risk, or perhaps the risk of a person incurring an above-average but nonmaximal exposure. Sometimes, agencies seek to regulate hazards so as to reduce the individual risk level (to the maximally exposed, high-end, or average individual) below 1 in 1 million. Sometimes, instead, a risk level of 1 in 100,000 or 1 in 10,000 or even 1 in 1000 is seen as de minimis. In short, the construct of individual risk plays a variety of decisional roles, but the construct itself is quite pervasive.This Article launches a systematic critique of agency decisionmaking keyed to individual risk. Part I unpacks the construct, and shows how it invokes a frequentist rather than Bayesian conception of probability. Part II surveys agency practice, describing the wide range of regulatory contexts where individual risk levels are wholly or partly determinative of agency choice: these include most of the EPA's major programs for regulating toxins (air pollutants under the Clean Air Act, water pollutants under the Clean Water Act and Safe Drinking Water Act, toxic waste dumps under the Superfund statute, hazardous wastes under RCRA, and pesticides under FIFRA) as well as the FDA's regulation of food safety, OSHA regulation of workplace health and safety risks, NRC licensing of nuclear reactors, and the CPSC's regulation of risky consumer products.In the remainder of the Article, I demonstrate that frequentist individual risk is a problematic basis for regulatory choice, across a range of moral views. Part III focuses on welfare consequentialism: the moral view underlying welfare economics and cost-benefit analysis. I argue that the sort of risk relevant to welfare consequentialism is Bayesian, not frequentist. Part IV explores the subtle, but crucial difference between frequentist and Bayesian risk. Part V moves beyond cost-benefit analysis and examines nonwelfarist moral views: specifically, safety-focused, deontological, contractualist, and democratic views. Here too, I suggest, regulatory reliance on frequentist individual risk should be seen as problematic. Part VI argues that current practices (as described at length in Part II) are doubly misguided: not only do they focus on frequentist rather than Bayesian risk, but they are also insensitive to population size.In short, the Article provides a wide ranging, critical analysis of contemporary risk assessment and risk regulation. The perspective offered here is that of the sympathetic critic. Risk assessment itself - the enterprise of quantifying health and safety threats - represents a great leap forward for public rationality, and should not be abandoned. Rather, the current conception of risk assessment needs to be reworked. Risk needs to be seen in Bayesian rather than frequentist terms. And regulatory choice procedures must be driven by population risk or some other measure of the seriousness of health and safety hazards that is sensitive to the size of the exposed population - not the risk that some particular person (whatever her place in the exposure distribution) incurs.

Development of risk assessment techniques for use in the field of explosives and ammunition

Abstract Criteria for estimating the risks involved with ammunition and explosives are presented against a background of the public's perception of risk. The criteria are presented in terms of a three band approach separated by two threshold risk levels. The upper and lower bands represent unacceptable and trivial risk situations respectively, whilst the middle band represents a region in which the risk levels must be reduced to as low a level as is reasonably practicable. Individual Risk criteria are presented for three groups of people: the workforce necessarily exposed to risk in the course of their daily work, those members of the workforce who do not need to be exposed to risk in order to do their work and the general public. In the case of Societal Risk only one set of criteria are presented on the basis that when a major incident involving large numbers of casualties occurs the public reaction does not discriminate in its perception of horror between members of the general public and members of the workforce. In addition to preserving life it is suggested that criteria are required to preserve stocks in situations where life itself may not be at risk. For this it is recommended that the propagation of initial initiation or explosion to other munitions nearby by sympathetic detonation should be prevented, as far as possible, by the maintenance of the current separation distances for magazines, updated where necessary as new knowledge becomes available and new explosives and munitions are developed. The present tentative proposals are compared with quantitative risk evaluation criteria proposed in other countries and in other industries.