Formal Safety Assessments quantitative risk assessment

O Neill, R.T., Biostatistical considerations in pharmacovigilance and pharmacoepidemiology linking quantitative risk assessment in pre-market licensure application safety data, post-market alert reports and formal epidemiological studies, Stat. Med., 17, 1851, 1998. 

Hazard Analysis. Recognizing that no plant can be perfectly safe, modem safety engineering has turned to techniques for the formal or quantitative assessment of risk [58]. Many techniques for formal analysis now exist [59,60]. They differ widely in scope and intention, and the Center for Chemical Process Safety [59] tabulates for each of them ... 

Conceptual Design Risk Assessment This review takes place at the concept and drawing level. Formal risk assessment methods, qualitative or quantitative, are used as required. The risk assessments are documented and approved by a multifunction team, of which the environmental, health, and safety personnel are a part. An independent reviewer, not a member of the project team, must also sign off on the risk assessments. Several people at this location have been dained to do Failure Mode and Effects Analyses. 

Whilst some comparative experimental evidence on the effectiveness of techniques such as testing and fault tolerance is available [FAA 1982 Knight and Leveson 1986b], the assessment, measurement and prediction of the contribution of formal methods to safety is a subject largely unresearched. There are two major reasons for this. First, there is very little experiment data. This is because there are relatively few instances of use of formd methods for safety-critical systems and even in these cases there is no systematic data collection [Bowen and Stavridou 1992]. But perhaps more fundamentally, quantitative evidence is sometimes perceived as inappropriate for qualitative improvement techniques such as formal methods. The two major schools of thought concerning risk analysis and assessment, qualitative and quantitative, are often at odds with each other. The quantitative school believes that probabilities are primarily reflections of the actual frequency of events, thus are objective and can be used for pr ictions of future events. 

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