Risk, subjective nature

By using a matrix to quantify and prioritize the risks the intrinsic subjective nature of risk assessment is not reduced, but a consistent framework for evaluating risk is provided. Although different matrices may be used for various applications, any risk assessment tool should include the elements of hazard severity and mishap probability. The risk level defined in the matrix represents the degree of risk associated with a hazard by considering these two elements. 

Regardless of incentives and information, travelers must be sufficiently competent to make good decisions. The belief that individuals are incompetent to make risky decisions arises from research on behavioral decision rules in complex situations and on attitudes. Traffic safety dedsions are suspect because risks may be misperceived and expected safety benefits may be undervalued. Ola Svenson and his colleagues, for example, report based on their attitudinal study that subjects show optimism bias they feel they are more skillful and safer than typical drivers. They state that drivers who feel immune may discount measures such as seat belts. A sununary of this and other representative evidence of representative incompetence is presented in column 2 of Table 2-1. Next to these results, in column 3, is the evidence of competence for each subject natural hazards and insurance, gambling, risk perception, and safety belt use. 

Due to the subjective nature of risk, no external agency, whether it be a regulatory body, a professional society or the author of a book such as this, can provide an objective value for ALARP. What risk is acceptable is very much in the eye of the beholder. 

Since significance tests are based on probabilities, their interpretation is naturally subject to error. As we have already seen, significance tests are carried out at a significance level, a, that defines the probability of rejecting a null hypothesis that is true. For example, when a significance test is conducted at a = 0.05, there is a 5% probability that the null hypothesis will be incorrectly rejected. This is known as a type 1 error, and its risk is always equivalent to a. Type 1 errors in two-tailed and one-tailed significance tests are represented by the shaded areas under the probability distribution curves in Figure 4.10. 

The designation of facilities (e.g., hospitals, natural gas plants) diat are subject to added risk and provision for dieir protection... 

The term risk assessment is not only used to describe the likelihood of an ad crse response to a chemical or physical agent, but it has also been used to describe the likelihood of any unwanted event. This subject is treated in more detail in tlie next Part. These include risks such as explosions or injuries in tlie workplace natural catastrophes injury or deatli due to various voluntary activities such as skiing, sky diving, flying, and bimgee Jumping diseases deatli due to natural causes and many others. ... 

Studies to investigate the safety and effectiveness of In Vitro Diagnostic (IVD) medical devices under intended use conditions are conducted as performance evaluations. They are considered to present less risk than clinical investigations since, by their nature, studies involving IVDs cannot have any direct impact on the health and safety of trial subjects. 

People who volunteer to be subjects in a drug study have a right to know what can and will happen to them if they participate (informed consent). The investigator is responsible for ensuring that each subject receives a full explanation, in easily understood terms, of the purpose of the study, the procedures to be employed, the nature of the substances being tested, and the potential risks, benefits, and discomforts. 

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