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Biomedical subjects

B Fischhoff

Publications and source records attributed to B Fischhoff.

At least 37 records · Page 2Linked to original sources

Risk perception and communication unplugged: twenty years of process.

Over the past twenty years, risk communication researchers and practitioners have learned some lessons, often at considerable personal price. For the most part, the mistakes that they have made have been natural, even intelligent ones. As a result, the same pitfalls may tempt newcomers to the field. This essay offers a personal (even confessional) history of the field over this period. It identifies a series of developmental stages. Progress through the stages involves consolidating the skills needed to execute it and learning its limitations. Knowing about their existence might speed the learning process and alert one to how much there still is to learn.

Communication↗

Designing risk communications: completing and correcting mental models of hazardous processes, Part I.

Many risk communications are intended to help the lay public make complex decisions about risk. To guide risk communicators with this objective, a mental models approach to the design and characterization of risk communications is proposed. Building on text comprehension and mental models research, this approach offers an integrated set of methods to help the risk communication designer choose and analyze risk communication content, structure, and organization. An applied example shows that two radon brochures designed with this approach present roughly the same expert facts as a radon brochure widely distributed by the U.S. EPA but meet higher standards on other content, structure, and organization criteria.

Communication↗

Evaluating risk communications: completing and correcting mental models of hazardous processes, Part II.

We propose a decision-analytic framework, called the mental models approach, for evaluating the impact of risk communications. It employs multiple evaluation methods, including think-aloud protocol analysis, problem solving, and a true-false test that allows respondents to express uncertainty about their answers. The approach is illustrated in empirical comparisons of three brochures about indoor radon.

Air Pollution, Indoor↗

Adolescent (in)vulnerability.

Three groups of subjects were asked to judge the probability that they and several target others (a friend, an acquaintance, a parent, a child) would experience various risks. Subjects were middle-class adults, their teenage children, and high-risk adolescents from treatment homes. All three groups saw themselves as facing somewhat less risk than the target others. However, this perception of relative invulnerability was no more pronounced for adolescents than for adults. Indeed, the parents were viewed as less vulnerable than their teenage children by both the adults and those teens. These results are consistent with others showing small differences in the cognitive decision-making processes of adolescents and adults. Underestimating teens' competence can mean misdiagnosing the sources of their risk behaviors, denying them deserved freedoms, and failing to provide needed assistance.

Adolescent↗

Giving advice. Decision theory perspectives on sexual assault.

What entitles us to give general advice? This general question is explored here in the specific context of providing responsible advice to women on how to make decisions about possible ways of reducing their risk of sexual assault. An approach is advanced that is a combination of decision analysis, used to provide a formal characterization of decision situations, and behavioral decision theory, used to provide a descriptive characterization of how people perceive those situations. The approach is illustrated with a set of studies using three diverse groups of women; a group of men, paralleling one of the groups of women; and a national sample of sexual assault experts. The approach is evaluated in terms of its feasibility, its strengths and weaknesses relative to alternative approaches, and its implicit position on broader political and philosophical issues.

Counseling↗

Evaluating voluntary risks of injury.

Making sound safety decisions requires accurate estimates of the costs of injuries and the benefits of their reduction. These estimates may be produced intuitively by citizens exposed to risk of injury, or formally, for analysts considering alternative safety policies. All such estimates rely on behavioral assumptions, regarding how people perceive and respond to to risks. They also rely on ethical assumptions, regarding how people should respond. The nature and validity of these assumptions are analyzed here, in order to provide a consumer's guide to techniques designed to evaluate risks and devise safety policies.

Cost-Benefit Analysis↗

Perceived driving safety and seatbelt usage.

Swedish and U.S. subjects judged their own driving skills and safety in relation to other drivers. As in earlier studies, most subjects showed an optimism bias: a tendency to judge oneself as safer and more skillful than the average driver, with a smaller risk of getting involved and injured in an accident. Different measures of the optimism effect were strongly correlated with one another, with driving experience and with the judged importance of human factors (as opposed to technical and chance factors) in causing accidents. Degree of optimism was positively, but weakly, correlated with reported seatbelt usage and worry about traffic accidents. Seatbelt usage was positively related to the extent to which belts are judged to be convenient and popular, and more modestly related to the belt's perceived contributions to safety. These results suggest that providing more information about the effectiveness of seatbelts may not be as efficient a way of increasing seatbelt usage as emphasizing other factors, such as comfort and social norms, which cannot be outweighed by optimism.

Accidents, Traffic↗

Powerline frequency electric and magnetic fields: a pilot study of risk perception.

The perception of the potential risk arising from human exposure to 50/60 Hz electric and magnetic fields was studied with a quasi-random sample of 116 well-educated, opinion leaders using the risk perception framework previously developed by Slovic, Fischhoff, and Lichtenstein. These individuals rated exposure to fields from transmission lines and electric blankets on a variety of scales that have been found useful in characterizing people's risk attitudes and perceptions. These judgments allowed us to conjecture about the likely desire for regulation of these potential hazards and the likely response to a publicized problem (e.g., an accident or ominous research finding) involving these two sources of exposure. Various forms of detailed information about 50/60 Hz fields were supplied to respondents. The provision of information produced modest, but statistically significant, changes in perceptions in the direction of greater concern about the risks. In response to questions of public policy, participants desired modest regulatory control of field exposure from transmission lines and little or no control of field exposure from appliances like electric blankets.

Electric Injuries↗

Cost-benefit analysis: an uncertain guide to public policy.

Recognition of the uncertainty inherent in social plans has generated a variety of formal approaches to coping with uncertainty. Perhaps the most heavily touted and widely adopted are variants of cost-benefit analysis. Such analyses ask whether the expected benefits from a proposed activity outweigh its expected costs. Although based on an appealing premise and supported by a sophisticated methodology, these procedures have a number of characteristic limits. One set of limits is imposed by the unavailability of necessary inputs to the analysis. Since neither the values nor the likelihood of many costs and benefits can be assessed by any formal computations, they must be derived by human judgment. Research has shown, however, that probability judgments are often quite unreliable and prone to systematic biases, while judgments of value are highly labile, changing with subtle (and formally irrelevant) shifts in the elicitation procedure. The second set of limits arises when one comes to assess the quality of analyses. There have been few systematic evaluations of formal analyses or attempts to develop a methodology for assessment. Again, one is forced to rely upon judgments which research has shown to be untrustworthy. A third set of limits is the inability of the procedures to address critical issues in the management process they are designed to abet. These issues include the acceptability of the political philosophy underlying such procedures, the feasibility of implementing their recommendations, and the generation of managerial options. The contribution of cost-benefit analysis may be enhanced by reducing whichever of these problems are tractable, acknowledging those that are not, and clarifying the responsible role of cost-benefit analysis in the management process.

Cost-Benefit Analysis↗

Modeling methylene chloride exposure-reduction options for home paint-stripper users.

Home improvement is a popular activity, but one that can also involve exposure to hazardous substances. Paint stripping is of particular concern because of the high potential exposures to methylene chloride, a solvent that is a potential human carcinogen and neurotoxicant. This article presents a general methodology for evaluating the effectiveness of behavioral interventions for reducing these risks. It doubles as a model that assesses exposure patterns, incorporating user time-activity patterns and risk-mitigation strategies. The model draws upon recent innovations in indoor air-quality modeling to estimate exposure through inhalation and dermal pathways to paint-stripper users. It is designed to use data gathered from home paint-stripper users about room characteristics, amount of stripper used, time-activity patterns and exposure-reduction strategies (e.g., increased ventilation and modification in the timing of stripper application, scraping, and breaks). Results indicate that the effectiveness of behavioral interventions depends strongly on characteristics of the room (e.g., size, number and size of doors and windows, base air-exchange rates). The greatest simple reduction in exposure is achieved by using an exhaust fan in addition to opening windows and doors. These results can help identify the most important information for product labels and other risk-communication materials.

Air Pollution, Indoor↗

A new scale for assessing perceptions of chance: a validation study.

BACKGROUND: Clinicians and researchers often wish to know how patients perceive the likelihoods of health risks. Little work has been done to develop and validate scales and formats to measure perceptions of event probabilities, particularly low probabilities (i.e., <1%). OBJECTIVE: To compare a new visual analog scale with three benchmarks in terms of validity and reliability. DESIGN: Survey with retest after approximately two weeks. Respondents estimated the probabilities of six events with the new scale, which featured a "magnifying glass" to represent probabilities between 0 and 1% on a logarithmic scale. Participants estimated the same probabilities on three benchmarks: two linear visual analog scales (one labeled with words, one with numbers) and a "1 in x" scale. SUBJECTS: 100 veterans and family members and 107 university faculty and students. MEASURES: For each scale, the authors assessed: 1) validity-the correlation between participants' direct rankings (i.e., numbering them from 1 to 6) and scale-derived rankings of the relative probabilities of six events; 2) test-retest reliability-the correlation of responses from test to retest two weeks later; 3) usability (missing/ incorrect responses, participant evaluation). RESULTS: Both the magnifier and the two linear scales outperformed the "1 in x" scale on all criteria. The magnifier scale performed about as well as the two linear visual analog scales for validity (correlation between direct and scale-derived rankings = 0.72), reliability (test-retest correlation = 0.55), and usability (2% missing or incorrect responses, 65% rated it easy to use). 62% felt the magnifier scale was a "very good or good" indicator of their feelings about chance. The magnifier scale facilitated expression of low-probability judgments. For example, the estimated chance of parenting sextuplets was orders of magnitude lower on the magnifier scale (median perceived chance 10(-5)) than on its linear counterpart (10(-2)). Participants' assessments of high-probability events (e.g., chance of catching a cold in the next year) were not affected by the presence of the magnifier. CONCLUSIONS: The "1 in x" scale performs poorly and is very difficult for people to use. The magnifier scale and the linear number scale are similar in validity, reliability, and usability. However, only the magnifier scale makes it possible to elicit perceptions in the low-probability range (<1%).

Adult↗

Women's views on breast cancer risk and screening mammography: a qualitative interview study.

BACKGROUND: To promote informed decision making about mammography, clinicians are urged to present women with complete, relevant information about breast cancer and screening. Understanding women's current beliefs may help guide such efforts by uncovering misunderstandings, conceptual gaps, and areas of concern. OBJECTIVE: The authors sought to learn how women view breast cancer, their personal risk of breast cancer, and how screening mammography affects that risk. METHODS: Forty-one open-ended semistructured telephone interviews with women selected from a national database by quota sampling to ensure a wide range in demographics of the participants. RESULTS: Almost all respondents viewed breast cancer as a uniformly progressive disease that begins in a silent curable form (typically found by mammograms) and, unless treated early, invariably grows, spreads, and kills. Some women felt that any abnormality found must be treated, even if it was not malignant. None had heard of potentially nonprogressive cancers, and when informed, most felt that the uncertain prognosis of such lesions reinforced the need to find and treat disease as soon as possible. Women expressed a wide range of views about their personal risk of breast cancer. Although some saw breast cancer as a central threat to their health, many others cited heart disease, other cancers, violence, and trauma as greater concerns. Most recognized the importance of "uncontrollable" factors for breast cancer such as age, sex, family history, and genetics. However, other "controllable" factors with little or no demonstrated link to breast cancer (e.g., smoking, diet, toxic exposures, "bad attitudes") were given equal or greater prominence, suggesting that many women feel considerable personal responsibility for their level of breast cancer risk. Similarly, although women recognized that mammography was not perfect, almost all believed that failure to have mammograms put one at risk for premature and preventable death. When asked how mammography worked, almost all repeated the message that "early detection saves lives," suggesting that advanced cancer (and perhaps most cancer deaths) reflected a failure of early detection. The belief in the benefit of early detection was so strong that some women advocated scaring other women into getting mammograms because it is "better to be safe than sorry." CONCLUSIONS: Women view breast cancer as a uniformly progressive disease rarely curable unless caught early. The exaggerated importance many attribute to a variety of controllable factors in modifying personal risk and the "danger" seen in failing to have mammograms may lead women diagnosed with breast cancer to blame themselves.

Adult↗

Communicating foodborne disease risk.

The food industry, like many others, has a risk communication problem. That problem is manifested in the public's desire to know the truth about outbreaks of foodborne diseases; ongoing concern about the safety of foods, additives, and food-processing procedures; and continued apathy regarding aspects of routine food hygiene. If these concerns are addressed in a coherent and trustworthy way, the public will have better and cheaper food. However, sloppy risk communication can itself cause public health damage. Because citizens are ill-equipped to discriminate among information sources, the food industry as a whole bears responsibility for the successes and failures of its individual members. We review risk communication research and practice for their application to the food industry.

Communication↗