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Acceptable-risk decisions are an essential step in the management of technological hazards. In many situations, they constitute the weak (or missing) link in the management process. The absence of an adequate decision-making methodology often produces indecision, inconsistency, and dissatisfaction. The result is neither good for hazard management nor good for society. This report offers a critical analysis of the viability of various approaches as guides to acceptable-risk decisions. This report seeks to define acceptable-risk decisions and to examine some frequently proposed, but inappropriate, solutions. 255 refs., 22 figs., 25 tabs.
Studies show that Nevada residents and state officials oppose the proposed high-level radioactive waste repository project at Yucca Mountain. Nevada residents view the Yucca Mountain repository as having extremely high risk; nuclear experts, in contrast, feel the risks are very low. These experts have suggested that public risk perceptions may be reduced by better program management, increased trust in the federal government, and/or by increased benefits and compensation for accepting a repository. The model described in this paper is designed to examine the relationship between risk perception and various strategies for risk management using a confirmatory multivariate method known as covariance structure analysis.
This chapter is concerned with conceptualizing the process by which a person makes decisions about gambles whose probabilities and payoffs are explicitly stated.
Thirty subsystems constituting a functioning motor vehicle, including brake, steering, suspension, engine, electrical, and fuel systems, were evaluated by individuals on a set of risk characteristic scales. These included overall vehicle riskiness, likelihood of severe consequences in the event of system failure, controllability of the vehicle, and observability of impending failure. An analysis of the resulting judgments revealed two composite factors, one representing the controllability of consequences and the other representing observability. Both factors were highly related to judgments of risk, desire for risk regulation, and anticipated recall compliance. A comparison of risk judgments with accident data suggested that for some vehicle systems, particularly those serving a communication function in the driving task, drivers may underestimate the actual risk they face when system performance has degraded.
Modern theories in cognitive psychology and neuroscience indicate that there are two fundamental ways in which human beings comprehend risk. The “analytic system” uses algorithms and normative rules, such as probability calculus, formal logic, and risk assessment. It is relatively slow, effortful, and requires conscious control. The “experiential system” is intuitive, fast, mostly automatic, and not very accessible to conscious awareness. The experiential system enabled human beings to survive during their long period of evolution and remains today the most natural and most common way to respond to risk. It relies on images and associations, linked by experience to emotion and affect (a feeling that something is good or bad). This system represents risk as a feeling that tells us whether it is safe to walk down this dark street or drink this strange‐smelling water. Proponents of formal risk analysis tend to view affective responses to risk as irrational. Current wisdom disputes this view. The rational and the experiential systems operate in parallel and each seems to depend on the other for guidance. Studies have demonstrated that analytic reasoning cannot be effective unless it is guided by emotion and affect. Rational decision making requires proper integration of both modes of thought. Both systems have their advantages, biases, and limitations. Now that we are beginning to understand the complex interplay between emotion and reason that is essential to rational behavior, the challenge before us is to think creatively about what this means for managing risk. On the one hand, how do we apply reason to temper the strong emotions engendered by some risk events? On the other hand, how do we infuse needed “doses of feeling” into circumstances where lack of experience may otherwise leave us too “coldly rational”? This article addresses these important questions.
The heart of prospect theory is the value function, proposing that the carriers of value are positive or negative changes from a reference point. Daniel Kahneman observed that if prospect theory had a flag, the value function would be drawn on it. The function is nonlinear, reflecting diminishing sensitivity to magnitude. When describing how human lives are valued, the function exposes profound incoherence. An individual life is highly valued and thus vigorously protected if it is the only life at risk. But that life loses its value when it is one of many endangered by a larger tragedy. Beyond this insensitivity, the function may actually decline when many lives at risk become mere numbers. The more who die, the less we care. Implications of this deadly ‘arithmetic of compassion’ for understanding and managing the risk from nuclear weapons are briefly discussed.
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In the context of health, safety, and environmental decisions, the concept of risk involves value judgments that reflect much more than just the probability and consequences of the occurrence of an event. This article conceptualizes risk as a game, in which the rules must be socially negotiated within the context of a specific problem. This contextualist view of risk provides insight into why technical approaches to risk management often fail with problems such as those involving radiation and chemicals, where scientific experts and the public disagree on the nature of the risks. It also highlights the need for the interested parties to define and play the game, thus emphasizing the importance of institutional, procedural, and societal processes in risk management decisions. This contextualist approach is illustrated using the problem of siting hazardous waste facilities.
Understanding drug risk perceptions is a prerequisite for designing better communication materials for patients and the public and, ultimately, for ensurin
Previous studies have concluded that when making inferences, people tend to ignore various kinds of normatively important information (e.g., sample size, base rates). The basis for such conclusions has typically been the similarity of responses across groups presented with widely discrepant values of that information. The experiments reported here convert earlier, between-subject designs to within-subject formats. Each subject made several judgments as one kind of information varied across a range of possible values. When information regarding base rates or predictive validity was varied, roughly two-thirds of the subjects changed their judgments in directions dictated by normative considerations, although the magnitudes of these changes were too small. There were no appreciable shifts in response to changes in sample size information. Apparently, people know (or can figure out) somewhat more than what they have been given credit for in the past. Of course, modest sensitivity in these somewhat artificial conditions is not inconsistent with completely ignoring such information when, as is usually the case, the world presents but one set of values.
