Risk, definitions

Hertzberg RC, MacDonell MM. 2002. Synergy and other ineffective mixture risk definitions. Sci Total Environ 288 31 -2. 

A further divide between risk analysts arises between realism and constructionism, but this debate can be seen as unifying positivist and relativist approaches. Constructionism considers how social and cultural perspectives influence risk definitions and interpretations [12]. In comparison, realists exclude social and cultural phenomena in their reference of risk, but do acknowledge their existence [12]. Constructionism resembles constrained relativism and does not represent the paradigms of the unconstrained relativists. For positivists and realists, acknowledging risk perceptions provides a potential framework to incorporate the risk perceptions into their process of risk analysis because risk perceptions can be subject to scientific analysis as social phenomena. 

Both models assume that the mixture under study is fully described in its chemical composition and that the dose-response curves of all compounds in the mixture are known. Both models are extensively covered in the literature both theoretically (Teuschler et al., 2002 Backhaus el al., 2003 Vighi et al., 2003) and when applied in case studies (Nirmalakhandan et al., 1997 Altenburger et al., 2000 Richardson et al., 2001 Backhaus et al., 2003). Using and interpreting either of the models, the reader has to be aware that both are mere simplifications of a very complex reality. A lot of cases can be found in the literature illustrating mixture effects not accounted for by the aforementioned models (Preston et al., 2000 Chu and Chow, 2002) and validity should be assessed case by case. A critical paper on how to deal with different mixture risk definitions has been written by Hertzberg and MacDonell (2002). 

In 1983 an important report [1] appeared which defined hazard and risk. It emanated from the United Kingdom s Royal Society, and resulted from a study group concerned with risk assessment for engineering and health risks. Definitions of hazard and risk were further elaborated by a Working Party of the United Kingdom s Institution of Chemical Engineers... 

Table 3.1 Selected Transportation Safety Risk Definitions...

Real option valuation (ROV) Recently, Gupta and Maranas (2004) revisited a real-option-based concept to project evaluation and risk management. This framework provides an entirely different approach to NPV-based models. The method relies on the arbitrage-free pricing principle and risk neutral valuation. Reconciliation between this approach and the above-described risk definitions is warranted. 

The P that is used to describe the risk is based on a background knowledge K, which includes data and models used. The U and P has to be seen in relation to the stakeholder S. Using these symbols, the risk definitions used in the frameworks 1-Vl can be summarised in the following way ... 

To further show the spectre of risk definitions adopted indifferent settings, reference is given to two important safety applications ... 

Many risk definitions describe risk as having only adverse consequences. There are, however, good reasons for not restricting the risk concept to undesirable consequences, and many definitions of risk accommodate both desirable and undesirable consequences. One may wish to avoid a discussion on whether a consequence is classified in the correct category. What is an undesirable consequence or outcome To some, an outcome can be undesirable, while it is desirable for others. In a short term context an event may be considered undesirable, but it may turn out that the consequences are highly desirable in a long term perspective. 

Heckmann I, Comes T, Nickel S (2015) A critical review on supply chain risk - definition, measure and modeling. Omega 52 119-132... 

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