Quantification of Risk

Once the standard error of estimate of the mean forecasted response has been estimated, i.e., the uncertainty in the total production rate, one can compute the probability level, a, for which the minimum total production rate is below some pre-determined value based on a previously conducted economic analysis. Such calculations can be performed as part of the post-processing calculations. 

We also tend to expose ourselves to situations and people that confirm our existing beUefs. For example, most people will watch TV channels that reinforce their political opinions. This can lead to shock when it turns out in an election that those beliefs did not constitute a majority opinion. 

People tend to notice items which are outstanding or different in some way. For example, someone entering their own house will not see all of the items of furniture, but she will notice that the television has been stolen or that a saucepan has boiled dry. Similarly anecdotes and emotional descriptions have a disproportionate impact on people s perceptions (as illustrated in the discussion to do with the Titanic tragedy provided earlier in this chapter). 

There are two kinds of people those who can count and those who can t count. 

Where possible, risk should be quantified. Doing so allows managers and regulators to have an objective understanding as to how well they are doing and how they compare with other facilities and companies. 

Analysis of system risk involves the use of mathematical terms that are used in statistical analysis and probability theory. Since some of these terms are also used by the public in a more general sense it is necessary to provide a precise definition for them. In particular, as has already been discussed, the words frequency, probability, and likelihood tend to be used interchangeably in normal conversation, yet, strictly speaking, they are different, and risk professionals should use them correctly. 

---

The Chemical Process Industry (CPI) uses various quantitative and qualitative techniques to assess the reliability and risk of process equipment, process systems, and chemical manufacturing operations. These techniques identify the interactions of equipment, systems, and persons that have potentially undesirable consequences. In the case of reliability analyses, the undesirable consequences (e.g., plant shutdown, excessive downtime, or production of off-specification product) are those incidents which reduce system profitability through loss of production and increased maintenance costs. In the case of risk analyses, the primary concerns are human injuries, environmental impacts, and system damage caused by occurrence of fires, explosions, toxic material releases, and related hazards. Quantification of risk in terms of the severity of the consequences and the likelihood of occurrence provides the manager of the system with an important decisionmaking tool. By using the results of a quantitative risk analysis, we are better able to answer such questions as, Which of several candidate systems poses the least risk Are risk reduction modifications necessary and What modifications would be most effective in reducing risk ... 

These experts collectively have knowledge of methyl parathion s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in Section 104(I)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

As is needed for all potential risks for chemical substances, an index of toxicity enables quantification of risk. Nevertheless, it only applies to risk by inhalation, which is yet the most common as well as insidious risk under normal working conditions with chemical substances. However, this approach should be treated with caution because of the difficulties inherent in toxicological risks. At this stage of the analysis it is essential to work in collaboration with the company doctor, whose total agreement is necessary. 

A third path for research is to study associations between system change and improvement, on the one hand, and public and consumer responses, on the other. In particular, what are the conditions for the development and maintenance of trustworthiness and satisfaction through organisational and communicative procedures With better knowledge of consumer demands and improved quantification of risks and benefits to health, the future trend is likely to point towards increased differentiation, with different products targeting consumer groups with different priorities. Some consumers will demand more convenience, while others will invest in participatory community farm schemes that allow direct involvement in the production and preparation of their food. 

Peter Lacouture, Associate Director, Clinical Research, The Purdue Frederick Company, Norwalk, Connecticut Dr. Fumio Matsumura, Associate Director, Toxic Substances Program, Institute of Toxicology and Environmental Health, University of California, Davis, California Dr. Frederick Oehme, Director, Comparative Toxicology Laboratories, Kansas State University, Manhattan, Kansas and Dr. Jack Radomski, Private Consultant, Jonesport, Maine. These experts collectively have knowledge of heptachlor and heptachlor epoxide s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in Section 104(i)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

---