High Risk or Low: How Location on a "Risk Ladder" Affects Perceived Risk

Efforts to explain risk magnitude often rely on a "risk ladder" in which exposure levels and associated risk estimates are arrayed with low levels at the bottom and high ones at the top. Two experiments were conducted to test the hypothesis that perceived threat and intended mitigation vary with the location of the subject's assigned level on the risk ladder. Subjects were New Jersey homeowners, asked to assume a particular level of radon or asbestos contamination in their homes, to read a brochure explaining the risk, and then to complete a questionnaire. Both studies found that the difference between an assigned level one-quarter of the way up the ladder and the same level three-quarters of the way up the ladder significantly affected threat perception; the effect on mitigation intentions was significant in only one of the studies. Variations in assigned risk also affected threat perception and mitigation intentions. Variations in test magnitude (e.g., 15 fibers per liter vs. 450 fibers per cubic foot, roughly equivalent risks) had no effect, nor did the distinction between radon and asbestos affect the dependent variables. These findings suggest that communicators can design risk ladders to emphasize particular risk characteristics.     

Some Criteria for Evaluating Risk Messages

Seven criteria are presented for use in evaluating communications designed to explain the magnitude of a risk. The criteria are: (1) comprehension (Does the audience understand the content of the communication?); (2) agreement (Does the audience agree with the recommendation or interpretation contained in the message?); (3) dose-response consistency (Do people facing a higher dose of a hazard perceive the risk as greater and/or show a greater readiness to take action than people exposed to a lower dose of this hazard?); (4) hazard-response consistency (Do people facing a hazard that is higher in risk perceive the risk as greater and/or show a greater readiness to take action than people exposed to a hazard that is lower in risk?); (5) uniformity (Do audience members exposed to the same level of risk tend to have the same responses to this risk?); (6) audience evaluation (Does the audience judge the message to have been helpful, accurate, clear, etc.?); and (7) types of communication failures (When different types of failures are possible, are the failures that occur generally of the more acceptable variety?). Each of these criteria is illustrated with data collected in a test of message formats designed to explain the risk presented by radon gas in a home.     

Risk Perception and Communication Unplugged: Twenty Years of Process1

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.     

Agency Communication, Community Outrage, and Perception of Risk: Three Simulation Experiments

Three experimental studies were conducted employing hypothetical news stories to compare the effects on reader risk perceptions of two situations: when agency communication behavior was reported to be responsive to citizens' risk concerns, vs. when the agency was reported to be unresponsive. In the first two experiments, news stories of public meetings filled with distrust and controversy led to ratings indicating greater perceived risk than news stories reporting no distrust or controversy, even though the risk information was held constant. This effect appeared clearly when the differences in meeting tone were extreme and subjects made their ratings from their recall of the stories, but it was much weaker when the differences were moderate and subjects were allowed to go back over the news stories to help separate risk information from conflict information. In the third experiment, news stories about a spill cleanup systematically varied the seriousness of the spill, the amount of technical information provided in the story, and the agency behavior and resulting community outrage. The outrage manipulation significantly affected affective and cognitive components of perceived risk, but not hypothetical behavioral intentions. Seriousness and technical detail had very little effect on perceived risk.     

Public Reliance on Risk Communication Channels in the Wake of a Cryptosporidium Outbreak

In the spring of 1993, about 39% of Milwaukee-area residents suffered through a nationally publicized illness brought about by cryptosporidium, a parasite that had infested the metropolitan drinking water supply. Our study, based on a telephone survey of 610 local adult residents, indicates that worry about becoming ill in the future with cryptosporidiosis relates more strongly and consistently to public reliance on, and use of, media for cryptosporidium information than do a range of risk perception and experience variables. We propose that more studies should take an audience-centered approach to understanding risk communication.     

Effect of Risk Ladder Format on Risk Perception in High- and Low-Numerate Individuals

Utilizing a random sample from the general population ( N = 257), we examined the effect of the radon risk ladder on risk perception, as qualified by respondents' numeracy. The radon risk ladder provides comparative risk information about the radon equivalent of smoking risk. We compared a risk ladder providing smoking risk information with a risk ladder not providing this information. A 2 (numeracy; high, low) × 3 (risk level; high, medium, low) × 2 (smoking risk comparison: with/without) between subjects experimental design was used. A significant ( p < 0.045) three-way interaction between format, risk level, and numeracy was identified. Participants with low numeracy skills, as well as participants with high numeracy skills, generally distinguished between low, medium, and high risk levels when the risk ladder with comparative smoking risk information was presented. When the risk ladder without the comparative information about the smoking risk was presented, low-numerate individuals differentiated between risk levels to a much lesser extent than high-numerate individuals did. These results provide empirical evidence that the risk ladder can be a useful tool in enabling people to interpret various risk levels. Additionally, these results allow us to conclude that providing comparative information within a risk ladder is particularly helpful to the understanding of different risk levels by people with low numeracy skills.     

The Determinants of Trust and Credibility in Environmental Risk Communication: An Empirical Study

This study examines a key component of environmental risk communication; trust and credibility. The study was conducted in two parts. In the first part, six hypotheses regarding the perceptions and determinants of trust and credibility were tested against survey data. The hypotheses were supported by the data. The most important hypothesis was that perceptions of trust and credibility are dependent on three factors: perceptions of knowledge and expertise; perceptions of openness and honesty; and perceptions of concern and care. In the second part, models were constructed with perceptions of trust and credibility as the dependent variable. The goal was to examine the data for findings with direct policy implications. One such finding was that defying a negative stereotype is key to improving perceptions of trust and credibility.     

The Nevada Initiative: A Risk Communication Fiasco

The U.S. Congress has designated Yucca Mountain, Nevada as the only potential site to be studied for the nation's first high-level nuclear waste repository. People in Nevada strongly oppose the program, managed by the U.S. Department of Energy. Survey research shows that the public believes there are great risks from a repository program, in contrast to a majority of scientists who feel the risks are acceptably small. Delays in the repository program resulting in part from public opposition in Nevada have concerned the nuclear power industry, which collects the fees for the federal repository program and believes it needs the repository as a final disposal facility for its high-level nuclear wastes. To assist the repository program, the American Nuclear Energy Council (ANEC), an industry group, sponsored a massive advertising campaign in Nevada. The campaign attempted to assure people that the risks of a repository were small and that the repository studies should proceed. The campaign failed because its managers misunderstood the issues underlying the controversy, attempted a covert manipulation of public opinion that was revealed, and most importantly, lacked the public trust that was necessary to communicate credibly about the risks of a nuclear waste facility.     

Improving Risk Communication

This paper explores reasons for difficulties in communicating risks among analysts, the laypublic, media, and regulators. Formulating risk communication problems as decisions involving objectives and alternatives helps to identify strategies for overcoming these difficulties. Several strategies are suggested to achieve risk communication objectives like improving public knowledge about risks and risk management, encouraging risk reduction behavior, understanding public values and concerns, and increasing trust and credibility.     

Presenting Uncertainty in Health Risk Assessment: Initial Studies of Its Effects on Risk Perception and Trust

Some analysts suggest that discussing uncertainties in health risk assessments might reduce citizens'perceptions of risk and increase their respect for the risk-assessing agency. We tested this assumption with simulated news stories varying simple displays of uncertainty (e.g., a range of risk estimates, with and without graphics). Subjects from Eugene, Oregon, read one story each, and then answered a questionnaire. Three studies tested between 180 and 272 subjects each. Two focus groups obtained more detailed responses to these stories. The results suggested that (1) people are unfamiliar with uncertainty in risk assessments and in science; (2) people may recognize uncertainty when it is presented simply; (3) graphics may help people recognize uncertainty; (4) reactions to the environmental problems in the stories seemed affected less by presentation of uncertainty than by general risk attitudes and perceptions; (5) agency discussion of uncertainty in risk estimates may signal agency honesty and agency incompetence for some people; and (6) people seem to see lower risk estimates (10^-6, as opposed to 10^-3) as less credible. These findings, if confirmed, would have important implications for risk 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.     

Nanotechnology Risk Communication Past and Prologue

Nanotechnologies operate at atomic, molecular, and macromolecular scales, at scales where matter behaves differently than at larger scales and quantum effects can dominate. Nanotechnologies have captured the imagination of science fiction writers as science, engineering, and industry have leapt to the challenge of harnessing them. Applications are proliferating. In contrast, despite recent progress the regulatory landscape is not yet coherent, and public awareness of nanotechnology remains low. This has led risk researchers and critics of current nanotechnology risk communication efforts to call for proactive strategies that do more than address facts, that include and go beyond the public participation stipulated by some government acts. A redoubling of nanotechnology risk communication efforts could enable consumer choice and informed public discourse about regulation and public investments in science and safety.     

Improving Risk Communication in Government: Research Priorities

Despite the increased interest in risk communication among government agencies, there is evidence that agencies'risk communication practices lag. We conducted a study to explore which risk communication research would be most important to improve government agencies'risk communication practices. Qualitative interviews and a survey of 145 risk communication experts based in academic institutions and government agencies explored how important research on each of 48 topics would be to improving agencies'risk communication efforts. Respondents identified topics within three areas as priorities for further research: 1) involving communities in agency decisionmaking; 2) communicating with communities of different races, ethnic backgrounds, and incomes; and 3) evaluating risk communication. Both practitioners and researchers responded to additional statements about agencies'risk communication practices with reservations about staff and managers'commitment to effective communication about environmental issues. We discuss the implications of these findings.     

Informing and Educating the Public About Risk

The objective of informing and educating the public about risk issues seems easy to attain in principle, but, in practice, may be difficult to accomplish. This paper attempts to illustrate why this is so. To be effective, risk communicators must recognize and overcome a number of obstacles that have their roots in the limitations of scientific risk assessment and the idiosyncrasies of the human mind. Doing an adequate job of communicating means finding comprehensible ways of presenting complex technical material that is clouded by uncertainty and inherently difficult to understand. The problems may not be insurmountable, however, if designers of risk information programs are sensitive to the difficulties.     

What Do We Know About Making Risk Comparisons?

The risks of unfamiliar technologies are often evaluated by comparing them with the risks of more familiar ones. Such risk comparisons have been criticized for neglecting critical dimensions of risky decisions. In a guide written for the Chemical Manufacturers Association, Covello et al. (¹) have summarized these critiques and developed a taxonomy that characterizes possible risk comparisons in terms of their acceptability (or objectionableness). We asked four diverse groups of subjects to judge the acceptability of 14 statements produced by Covello et al. as examples of their categories. We found no correlation between the judgments of acceptability produced by our subjects and those predicted by Covello et al. .     

Risk Communication and Foodborne Illness: Message Sponsorship and Attempts to Stimulate Perceptions of Risk

Foodborne illness represents a serious health hazard in the United States. Since foodborne illness can often be prevented by an individual's behavior, messages aimed at promoting safe food-handling behaviors should be a major tool to reduce the incidence of foodborne illness. This article argues that to achieve adoption of safe food-handling practices in the home, food-safety messages should both stimulate risk perceptions and promote self-efficacy, feelings that one can successfully enact recommended behaviors. A content analysis of nationally distributed food-safety messages questioned if messages incorporated these features. Since food-safety communicators operate in complex environments with multiple and sometimes competing objectives, this study also questioned if sponsorship of foodborne illness prevention messages was related to the amount of content designed to alter risk perceptions associated with foodborne illness. Results of the quantitative content analysis found that copywriters generally included content designed to stimulate risk perception about foodborne illness but virtually ignored self-efficacy needs of the audience. A marked difference in tendencies to stimulate risk perceptions was found based on sponsorship. Both in volume and proportion, results show that governmentally sponsored messages more aggressively attempted to heighten risk perceptions associated with foodborne illness than did messages sponsored by privately funded communicators.     

Stability and Inoculation of Risk Comparisons'' Effects Under Conflict: Replicating and Extending the "Asbestos Jury" Study by Slovic et al.

Promotion or criticism of risk comparisons in risk communication has far exceeded empirical tests of their effects. Slovic et al. (1990) experimented with a hypothetical jury trial in which an asbestos-installing firm was accused of subjecting school occupants to unreasonable risk. A risk comparison sharply reduced subjects' estimates of risk and judgments that the firm was guilty, but a critique of the risk comparison had risk estimates and guilt judgments rebounding to the original (without risk comparison) level. Slovic et al. concluded that risk comparisons' effects were highly unstable, at least in conflict-ridden situations such as a jury trial. The present study replicates and extends this important study, using the same stimuli and questions. The respective effects of the risk comparison and the critique recurred, although much less sharply than in Slovic et al. Moreover, judgments of guilt, risk, and other aspects of the case seemed shaped more by demographics and beliefs about risk generically (e.g., about the likelihood of cancer after exposure to a carcinogen) than by either risk comparison or critique. A variant design, in which the defense's expert witness dismissed potential criticisms of the risk comparison, appeared to "inoculate" people against shifting their views after seeing the critique. Overall, these results show that risk comparisons might change some beliefs about risks in conflict and that "inoculation" can reduce vulnerability to criticism. However, the results also show strong limits on effects of both comparisons and their critiques: they shifted only a minority of judgments and had small effects relative to people's social locations and prior risk beliefs.     

The Evolving Field of Risk Communication

The 40th Anniversary of the Society for Risk Analysis presents an apt time to step back and review the field of risk communication. In this review, we first evaluate recent debates over the field's current state and future directions. Our takeaway is that efforts to settle on a single, generic version of what constitutes risk communication will be less productive than an open-minded exploration of the multiple forms that comprise today's vibrant interdisciplinary field. We then review a selection of prominent cognitive, cultural, and social risk communication scholarship appearing in the published literature since 2010. Studies on trust in risk communication messengers continued to figure prominently, while new research directions emerged on the opportunities and critical challenges of enhancing transparency and using social media. Research on message attributes explored how conceptual insights particularly relating to framing, affective and emotional responses, and uncertainty might be operationalized to improve message effectiveness. Studies consistently demonstrated the importance of evaluation and how varying single attributes alone is unlikely to achieve desired results. Research on risk communication audiences advanced on risk perception and multiway engagement with notable interest in personal factors such as gender, race, age, and political orientation. We conclude by arguing that the field's interdisciplinary tradition should be further nurtured to drive the next evolutionary phase of risk communication research.     

Direct Inference, Probability, and a Conceptual Gulf in Risk Communication

Differences in the conceptual frameworks of scientists and nonscientists may create barriers to risk communication. This article examines two such conceptual problems. First, the logic of "direct inference" from group statistics to probabilities about specific individuals suggests that individuals might be acting rationally in refusing to apply to themselves the conclusions of regulatory risk assessments. Second, while regulators and risk assessment scientists often use an "objectivist" or "relative frequency" interpretation of probability statements, members of the public are more likely to adopt a "subjectivist" or "degree of confidence" interpretation when estimating their personal risks, and either misunderstand or significantly discount the relevance of risk assessment conclusions. If these analyses of inference and probability are correct, there may be a conceptual gulf at the center of risk communication that cannot be bridged by additional data about the magnitude of group risk. Suggestions are made for empirical studies that might help regulators deal with this conceptual gulf.