Risk Appraisal

Definition

The term risk appraisal refers to an evaluation of the chances that a future event may occur. Similar terms include risk assessment, risk perception, perceived likelihood, and perception of vulnerability. One might appraise the risk of globally significant events (e.g., terrorism, natural disasters) as well as those that are personally relevant (e.g., losing a child, developing a disease). People's beliefs about risk influence a wide variety of decisions and behaviors in many life domains including careers, relationships, and health. As examples, college students are relatively less likely to choose careers in which the chances of getting a job are low, and women are unlikely to get mammographies if they do not feel at risk for breast cancer. If risk appraisals are incorrect, they may lead to faulty decision making and counterproductive behavior, necessitating the development of strategies to correct these appraisals. Laypeople evaluate risk very differently than experts do, and such differences can have public policy implications.

Measurement

A common method of assessing perceptions of risk is to ask individuals whether an event will or will not happen, or have them estimate the chances it will happen on a percentage (0%–100%) scale. One problem with the latter approach is that people often have difficulty thinking about risk in numerical terms and think about probabilities differently than experts do. For example, when people estimate that an event has a 50% chance of happening, what they really mean is that it might or might not happen and they are not sure. Several other numerical measures attempt to minimize this problem, such as a magnifier scale in which the lower end of a percentage scale (between 0% and 1%) is divided into smaller units to encourage respondents to use this part of the scale for rare events. Another approach is to have individuals make relative judgments, such as how the risk of one event compares with that of another (e.g., having cancer vs. having heart disease) or how one person's risk compares with that of another person or persons. Still another is to use a verbal scale (ranging, for example, from “very unlikely” to “very likely”). Any of these measures can be designed to be conditional on some behavior (e.g., “If you continue to smoke, what are your chances of getting lung cancer?”). Affective risk appraisals such as worry or the feeling that something will happen can also be assessed.

The choice of measures can greatly influence the findings of a given study. For example, people's verbal risk appraisals are more sensitive to new information than are their numerical risk appraisals, and people may be pessimistically biased regarding their absolute risk of an event yet optimistically biased about their risk relative to that of their peers. Affective perceptions of vulnerability (e.g., “feeling at risk”) are sometimes more predictive of behaviors such as vaccination than are cognitive perceptions of vulnerability.

Errors in Risk Appraisal

People often make errors when appraising their risk. They tend to overestimate small risks and underestimate large risks, and perceive positive events as more likely to occur than negative events. A disproportionate [Page 757]number of individuals consider their level of personal risk to be lower than that of their peers, a bias called unrealistic optimism. People also tend to overestimate the risk of outcomes that have a low probability of occurring and yet result in major consequences (e.g., nuclear reactor explosions, airplane accidents). These events are often marked by a feeling of dread, lack of control, and the potential for extremely negative outcomes. Indeed, people often believe that high risk initiatives have low benefit, whereas experts believe exactly the reverse (as in the case of nuclear energy).

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