Expert opinion, risk assessment

Extrapolation methods were tested against critical scientific opinion with several relevant data sets for key model substances and mixtures to stimulate critical assessment of the extrapolation procedures at a stakeholder workshop held in Florida. The stakeholder workshop was held with participation from 31 experts in risk assessment from the United States, Europe, and other countries. Participants were selected from academia, government regulatory bodies, industry, risk managers, and decision makers, and had diverse backgrounds (e.g., ecotoxicologists, ecologists, environmental... 

The severe accident research program improved public risk assessment, reduced uncertainties, and the reliance on subjective expert opinion. To close two severe accident issues in NRC s Severe Accident Research Plan (NUREG-1365) Mark I Liner Attack and Direct Containment Heating (DCH) were addressed with a new approach using the Risk Oriented Accident Analysis Method (ROAAM) (Theofanous, 1994, 1989). The resolution of the Mark-I Liner Attack issue constitutes the first full demonstration of ROAAM. It emphasizes the determinism and provides a basis for synergistic collaboration among experts through a common communication frame. 

In the authors opinion, even if imperfect, the CLL approach is preferable to apply for ecosystem risk assessment than a qualitative EcoRA based mainly on expert judgment. 

Central to any risk assessment is a model of causality. At the onset, a conceptual model is needed that identifies a plausible cause-effect relationship linking stressor exposure to some effect. Most ecological risk assessments rely heavily on weight-of-evidence or expert opinion methods to foster plausibility of the causal model. Unfortunately, such methods are prone to considerable error (Lane et al. 1987 Hutchinson and Lane 1989 Lane 1989), and attempts to quantify that error are rare. Although seldom used in risk assessment, Bayesian methods can explicitly quantify the plausibility of a causal model. 

Mosleh, A., Bier, V. M., and Apostolakis, G A critique of current practice for the use of expert opinion in probabilistic risk assessment. Reliab. Eng. Syst. Saf. 20, 63 (1988). 

The National Institute of Public Health, Department of Air Hygiene supports an Expert Group for Ambient Air Hygiene. The activities comprise the processing of expert opinions, health risk assessments, legislative activities, tuition, and consulting. 

Ouellet D. Benefit-risk assessment the use of clinical utility index. Expert Opinion on Drug Safety March 2010 9(2) 289-300. 

Mosleh, A. Apostolakis, G. 1986. The Assessment of probability distributions from expert opinions with an application to Seismic Fragility Curves. Risk Analysis, 6, No. 4 447 61. 

A mixture of qualitative and quantitative methods was used in this work. These include reliability analysis, eapital investment costs, safety, feasibility and environmental impaet assessment (ElA). Tools used include failure mode and effect analysis (FMEA), environmental impaet assessment, and risk analysis. FMEA was used to conduct a reliability analysis, EIA was used to calculate the concentration of the flared gas eomposition partieles affeeting the local environment, and risk assessment was employed to find out the hazards and exposure in the case study in order to assure safety. Cost estimation was used to ealculate the capital investment cost for each option considered. Information and expert opinions were eaptured through interviews and questionnaires. 

In the safety domain, we also face the same severe limit on the availability of data to quantify failure probabilities. Expert opinion in the form of subjective probabilities has been a dominant source for failure probabilities in quantifying risk in safety science. Cooke (1991) and Cooke and Goossens (2000) presented a structured expert judgment procedure to combine experts opinion in a scientifically defensible way. The overall goal of the method developed by these authors is to achieve rational consensus in the resulting assessments, and thus to enable the information of diverse experts or stakeholders to be incorporated into the process by which the results are reached. We have successfully applied this approach in a series of studies in the field of aviation and chemical industry studies (Ale et al. 2009 2011 2013) with Bayesian Belief Networks (BBNs) quantification. Although the structure expert judgement is not yet implemented in the security world, the scientific proof of such a method can be implemented in this domain. 

Bayesian statistics are a generic method that is well suited for assessment of urban security related risks. In particular, with corresponding effort, BBNs can be applied to model severity of consequences for different scenarios based on expert opinion. 

Risk assessments commonly use frequencies of observed events (i.e. historical data) as a major part of the basis for the risk assessment. To decide whether some available historical data is relevant for the future situation may be challenging. When in lack of data, or when we believe the past is not relevant for assessing the future, we turn to experts who possess knowledge that we consider relevant and want to apply in the assessments. We ask the experts to provide their opinion, and quantify degrees of belief using subjective probabilities. 

Risk assessment plays the key role in any management activity. There are various alternative approaches to risk assessment (Kaplan Garrick 1981, Zio 2007). Most popular is the qualitative approach, based on expert opinions (Flyvbjerg 2006). The basis of this analysis is to classify the identified risks in accordance to the likelihood of their occurrence and the gravity of their consequences. 

After evaluating the planned barriers as well as the influencing factors, then, the assessment of the occupational hazards within the defined susceptible hazards/risks exposed area need to be performed. The susceptible hazards/risks exposed area can be defined as per expert s judgement (opinions) and past experience. For example, a checklist analysis which is an experience based approach, can be used to identify known types of occupational hazards, potential accident situations, or design deficiencies (Neogy et al., 1996). Thereafter, the hazards needs to be classified as well as prioritise based on the standards, regulations and statutory requirements. 

---