Hello dear friends, This article on Solsarin is going to give you some information about “which one of the following poses a great danger”.
Understanding Hazards and Risks
Throughout recorded history people have engaged in hazardous activities, and governments have taken action to control some of those activities in the public interest. But in recent times the hazards of greatest concern, and knowledge about them, have changed in ways that make informed decisions harder to reach.
Once the focus was simply on the presence or absence of danger. If food was “adulterated,” if water was determined to be “impure,” if a bridge or dam was declared “unsafe,” or if a workplace was “dangerous,” action was called for. When people called on the government to take action, they wanted simple, clear-cut measures: ban the sale of the food, supply pure water, condemn the bridge, eliminate the workplace hazard. But with increased understanding of the nature of the choices, it has become harder to maintain a simple view. Responsible decision-makers need to know more about the alternatives than that one of them is hazardous.
In this chapter, we outline the many kinds of knowledge a well-informed decision requires and the ways in which this knowledge is often incomplete and uncertain. We show how, under such conditions, the judgments of both experts and nonexperts can be affected by preexisting biases and cognitive limitations and how human values and concerns inevitably enter into the analytic process. These factors often lead experts to disagree with each other and with non-experts about the significance of risks, even when the facts are not in dispute.
TOWARD QUANTIFICATION OF HAZARDS
One reason decision-makers need more knowledge is that it has become clear that eliminating one danger can create a new one. To rid the water supply of organisms that cause typhoid and other infectious diseases, water has been chlorinated since early in this century. This action resulted in chemical reactions in the water that produced chloroform and other carcinogenic chlorinated hydrocarbons.
To choose between the dangers, one must answer difficult questions: Which danger is more worth avoiding? How much decreased danger from typhoid is enough to justify a certain amount of increased danger of cancer? Do experts agree that there will be fewer deaths from chlorination-induced cancer than there once were from typhoid, but is that enough information to make a decision? It may be important to consider that typhoid and cancer are very different kinds of dangers. Typhoid is an acute disease and cancer is a chronic one; typhoid is much more treatable; and there are alternatives to chlorination for preventing it, although the alternatives also present hazards, as yet poorly understood.
Society is faced with many choices that trade one danger for another and that raise similar questions. For instance, regulated commercial canning of food reduced the danger of botulism compared with home canning, but the use of lead solder in “tin” cans introduced a toxin not present in home canning jars. Lighter automobiles use less fuel and generate less air pollution, but in a collision with an older, heavier vehicle they are more dangerous to their occupants.
Societal choices also involve the benefits associated with hazards and the costs of hazard reduction. Industries that pollute air and water also provide jobs and profits; before requiring pollution controls, public officials usually want to consider the probable effects of the available options on those benefits. Cities may install traffic lights to reduce fatalities and injuries, but officials usually want to consider whether this is the best way to spend scarce revenues. Thus decision-makers want good estimates of how much each alternative will reduce hazards so that they can judge the potential benefits against the potential costs.
Decision-makers need detailed knowledge because it has become clear that making the world safer for most people can make it more dangerous for some. Pesticides and herbicides have helped make wholesome food more available and have helped improve the diets of low-income consumers, but they expose agricultural workers to hazardous chemicals and can be a significant polluter of water supplies. The total danger to society may have decreased greatly, but that knowledge may be of no comfort to farmworkers. Nuclear power offers some people the benefit of cleaner air but may expose different people to radioactivity in the event of an accident. How is society to weigh small benefits to many against what are sometimes larger dangers for a relative few?
Decision-makers need detailed knowledge for another reason as well: the hazards of greatest concern today are more difficult to observe and evaluate than the major hazards of the past. Half a century ago most of the major health and safety hazards were of immediate onset: accidents, bacterial infections, poisonings, and the like. It can be hard to know what the hazards of a substance or activity are before a generation of experience has accumulated.
To make informed choices, it helps to look carefully and analytically at the hazards each alternative entails. It is important to develop quantitative knowledge: How much cancer might be caused by chlorinating water? How much pesticide is farm workers exposed to? For this kind of analysis, some conceptual distinctions are useful. The most basic of these is between “hazard” and “risk.”
An act or phenomenon is said to pose a hazard when it has the potential to produce harm or other undesirable consequences to some person or thing. The magnitude of the hazard is the amount of harm that may result, including the number of people or things exposed and the severity of consequence. Thus an area that experiences a severe hurricane once in 200 years faces the same hazard but only one-tenth the risk of a similar area that experiences an equally severe hurricane once in 20 years. The concept of risk makes clear that hazards of the same magnitude do not always pose equal risks.
Risks of the same magnitude do not always pose equal concerns, either. Most quantitative measures of risk combine the undesirability of a hazard and its probability of occurrence into a single summary measure. Some ways of characterizing risk take such concerns into account. These involve calculating separate risk estimates for each hazardous effect, giving heavier weight to qualitative characteristics of risk (e.g., Fischhoff et al., 1984; Okrent, 1980), and using explicit measures of values and risk attitudes (Raiffa, 1968).
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KNOWLEDGE NEEDED FOR RISK DECISIONS
Understanding the risks is not enough, because organizations and individuals never choose between risks. Rather, they choose between options, each of which presents some risks. Each also presents benefits, which are as crucial to the choices as the risks are. Understanding risks can be difficult, but understanding the benefits of a set of decision alternatives can be as difficult. Both kinds of knowledge are needed for an informed choice.
This section outlines the many kinds of relevant knowledge. It summarizes four kinds of knowledge decision-makers need: (1) about risks and benefits associated with a particular option, (2) about alternative options and their risks and benefits, (3) about the uncertainty of the relevant information, and (4) about the management situation.
Information About the Nature of Risks and Benefits
“Risk assessment” is the term generally used to refer to the characterization of the potential adverse effects of exposures to hazards. Risk assessment, therefore, addresses the questions listed below. “Benefit assessment,” a term not commonly used, addresses many similar questions. Some benefit questions are mentioned below, in parentheses.
- 1. What are the hazards of concern as a consequence of a substance or activity? How serious is each potential consequence? Is it reversible? (Who benefits and in what ways?)
- 2. What is the probable exposure to each hazard in a total number of people or valued things? How do the exposures cumulate over time? A single exposure over a short period of time can have effects different from those due to exposure to the same amount of a hazard in several episodes or chronically at low levels over a longer period of time. (How many people benefit? How long do the benefits last?)
- 3. What is the probability of each type of harm from a given exposure to each hazard? How potent is the hazardous substance or activity at the relevant exposures?
- 4. What is the distribution of exposure? In particular, which groups receive a disproportionate share of the exposure? (Which groups get a disproportionate share of the benefits?)
- 5. How do exposures interact with exposures to other hazards? Sometimes one exposure can make people more sensitive to another hazard—a synergistic effect—and, occasionally, exposure to one hazard may decrease sensitivity to another—a blocking effect.
- 6. What are the qualities of the hazard? For instance, do those exposed have an option to reduce or eliminate their exposure (and at what cost)? Would harm come to exposed people one at a time or as a mass, in a potential catastrophe? Is the hazard deadly or not? Does the harm take the form of accident or illness, acute or chronic disease, damage to the young or the old, to the living or the unborn? If the hazard is an illness, is it treatable? Is it a dread illness, such as cancer, or one that creates less of an emotional reaction? Table 2.1 lists qualities of risk that make a difference in most people’s judgments. (What are the qualities of the benefits? Do they appear as increased income, saved time, physical comfort, improved health, more stable ecosystems, more beautiful surroundings, improved welfare for low-income people or the elderly, or in other forms?)
- 8. What is the total population risk, taking into account all of the above? To arrive at such an estimate, one must somehow calculate a summation across different types of harm, people of different sensitivities, and exposures to the hazard in different amounts and in combination with various other hazards. (What is the total benefit?)
Thanks for your attention.