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.     

Network Evening News Coverage of Environmental Risk

ABC, CBS, and NBC's carefully crafted and expensively produced evening news broadcasts devoted 1.7% of their air time to 564 stories about man-made environmental risks during the period from January 1984 to February 1986. Little relationship was found between amount of coverage and public health risk. Instead, the networks appeared to be using traditional journalistic determinants of news (timeliness, proximity, prominence, consequence, and human interest) plus the broadcast criterion of visual impact to determine the degree of coverage of risk issues. Government, industry, and citizens accounted for two-thirds of the sources cited by the networks. Experts and spokespersons for environmental advocacy groups were sparsely used as sources. Given the media's need for news pegs, acute and chronic risk stories were covered differently. Acute risk stories were reported in a clearly defined cycle, peaking on the second day with on-the-scene reports and film-clips of devastation. In keeping with a decrease in visual drama, later reports were shorter and emphasized legal and political considerations. Chronic risk coverage followed the release of new scientific, legal, or political information.     

A Model of Consumers' Risk Perceptions Toward Recombinant Bovine Growth Hormone (rbGH): The Impact of Risk Characteristics

This study estimates the effect risk characteristics, described as outrage factors by Hadden, have on consumers' risk perceptions toward the food-related biotechnology, recombinant bovine growth hormone (rbGH). The outrage factors applicable to milk from rbGH treated herds are involuntary risk exposure, unfamiliarity with the product's production process, unnatural product characteristics, lack of trust in regulator's ability to protect consumers in the marketplace, and consumers' inability to distinguish milk from rbGH treated herds compared to milk from untreated herds. An empirical analysis of data from a national survey of household food shoppers reveals that outrage factors mediate risk perceptions. The results support the inclusion of outrage factors into the risk perception model for the rbGH product, as they add significantly to the explanatory power of the model and therefore reduce bias compared to a simpler model of attitudinal and demographic factors. The study indicates that outrage factors which have a significant impact on risk perceptions are the lack of trust in the FDA as a food-related information source, and perceiving no consumer benefits from farmers' use of rbGH. Communication strategies to reduce consumer risk perceptions therefore could utilize agencies perceived as more trustworthy and emphasize the benefits of rbGH use to consumers.     

Perception of Risk and Credibility at Toxic Sites

This study integrates previous research methodologies to compare the risk perceptions and responses to risk messages of agency personnel and neighbors of Superfund sites in Michigan. The integration attempted and the focus on risk messages are shaped by a critical review of the social amplification conceptual framework. The study involved all four agency groups and three groups of site neighbors actively involved in Superfund planning across the state. The first part of the study utilized the psychometric techniques of hazard rating and hazard profiles that had not previously been used in studies involving stakeholders. While agency personnel responded similarly to experts in previous studies, the responses of individuals in the neighbor groups reflected experience with toxic sites and were dissimilar to previous ratings by the general public. The second part of the study consisted of a hypothetical toxic site scenario that focused on specific risk messages at different times in the site history. Results indicate that the difference in perception of risk occurs after the first testing at a site, and that dramatic differences arise between agency and resident groups regarding the credibility of information sources and the need for independent testing. A general lack of trust in the Superfund program was demonstrated by all groups. The results indicate that problems of institutional credibility and program adequacy cannot be addressed by better risk communication.     

Fishing in a Polluted Estuary: Fishing Behavior, Fish Consumption, and Potential Risk

People make subjective judgments about hazards relying on what they know and feel. These risk perceptions may be based on accurate or inaccurate information and are often optimistically biased. The existence of uncertainties in the evaluation of many environmental hazards effects how risks are perceived. This paper examines fish consumption and risk perception of urban fishermen in the New York/New Jersey estuary, in areas where there were consumption advisories. We interviewed 318 fishermen and crabbers in the Arthur Kill, Raritan Bay, and New Jersey shore. Fish were eaten an average of at least four times per month in all regions, but fishermen in the Arthur Kill fished most frequently, averaging over eight times per month. Although 60% of fishermen and crabbers in the Arthur Kill reported hearing warnings about consuming fish caught in these waters, 70% of fishermen and 76% of crabbers said they ate their catch. Significantly fewer fishermen in the Bay and Shore regions had heard warnings (28% and 30%, respectively), and more reported consuming their catch (88% and 82%, respectively). In all regions, most people thought that the fish were safe to eat, many believing they were "fresher" than store bought fish. Thus, most people ignored the consumption advisories in effect for these waters. Some of these people are consuming high quantities of fish and crabs, and thus are exposed to potentially deleterious levels of contaminants. In general, people failed to consider the possibility of chronic effects and did not perceive that this enjoyable, familiar pastime could be hazardous. Further, fishermen generally had great confidence in their own knowledge, which proved to be inaccurate in many cases, and often expressed distrust in the information source (government). Clearly, simply issuing consumption advisories is insufficient to promote risk-reducing behavior.     

Risk,Media, and Stigma at Rocky Flats

Public responses to nuclear technologies are often strongly negative. Events, such as accidents or evidence of unsafe conditions at nuclear facilities, receive extensive and dramatic coverage by the news media. These news stories affect public perceptions of nuclear risks and the geographic areas near nuclear facilities. One result of these perceptions, avoidance behavior, is a form of "technological stigma" that leads to losses in property values near nuclear facilities. The social amplification of risk is a conceptual framework that attempts to explain how stigma is created through media transmission of information about hazardous places and public perceptions and decisions. This paper examines stigma associated with the U.S. Department of Energy's Rocky Flats facility, a major production plant in the nation's nuclear weapons complex, located near Denver, Colorado. This study, based upon newspaper analyses and a survey of Denver area residents, finds that the social amplification theory provides a reasonable framework for understanding the events and public responses that took place in regard to Rocky Flats during a 6-year period, beginning with an FBI raid of the facility in 1989.     

Public Meetings and Risk Amplification: A Longitudinal Study

This article offers longitudinal data tracking people who did and did not attend a series of public meetings in an upstate New York rural community grappling with the expansion of an existing solid waste landfill and remediation of an adjacent inactive hazardous waste site. Before and after the public meetings, mailed questionnaires measured risk perceptions and perceived credibility of risk managers (here, the state government agencies and the responsible industry) conducting the meetings. Respondents at each measurement point included meeting attendees and nonattendees, with some fluctuation over time when attendees at one measurement point were nonattendees at the next and vice versa. The results from the first survey indicate that following the first two public meetings, attendees perceived greater risks from the waste sites than did nonattendees; attendees also perceived the risk managers as less credible. After the third public meeting, the results showed that attendees' risk perceptions remained steady; however, perceptions of government agency credibility significantly decreased. After the fourth public meeting, the survey found that attendees' risk perceptions were again not significantly different, whereas perceptions of government agency credibility increased significantly. The industry's credibility also increased, though only among attendees who had attended the most recent public meeting, not among attendees who had attended both the third and fourth public meetings. For nonattendees, risk perceptions and credibility ratings did not change. The discussion examines how distinctive characteristics of communication at each public meeting may have resulted in different effects and proposes hypotheses for future research.     

Perceived Risk, Dread, and Benefits

This paper uses regression techniques to take a second look at a classic risk-perception data set originally collected by Paul Slovic, Sarah Lichtenstein, and Baruch Fischhoff. As discussed in earlier studies, the attributes expected mortality, effects on future generations, immediacy , and catastrophic potential all significantly affect risk ratings. However, we find that perceived risk and dread show different regression patterns; most importantly, only perceived risk ratings correlate with expected mortality. In addition, average risk ratings are found to be significantly affected by perceived individual benefits, which suggests that perceptions of risk are net rather than gross indicators of harm.     

Risk Comparisons, Conflict, and Risk Acceptability Claims

Despite many claims for and against the use of risk comparisons in risk communication, few empirical studies have explored their effect. Even fewer have examined the public's relative preferences among different kinds of risk comparisons. Two studies, published in this journal in 1990 and 2003, used seven measures of "acceptability" to examine public reaction to 14 examples of risk comparisons, as used by a hypothetical factory manager to explain risks of his ethylene oxide plant. This study examined the effect on preferences of scenarios involving low or high conflict between the factory manager and residents of the hypothetical town (as had the 2003 study), and inclusion of a claim that the comparison demonstrated the risks' acceptability. It also tested the Finucane et al. (2000) affect hypothesis that information emphasizing low risks-as in these risk comparisons-would raise benefits estimates without changing risk estimates. Using similar but revised scenarios, risk comparison examples (10 instead of 14), and evaluation measures, an opportunity sample of 303 New Jersey residents rated the comparisons, and the risks and benefits of the factory. On average, all comparisons received positive ratings on all evaluation measures in all conditions. Direct and indirect measures showed that the conflict manipulation worked; overall, No-Conflict and Conflict scenarios evoked scores that were not significantly different. The attachment to each risk comparison of a risk acceptability claim ("So our factory's risks should be acceptable to you.") did not worsen ratings relative to conditions lacking this claim. Readers who did or did not see this claim were equally likely to infer an attempt to persuade them to accept the risk from the comparison. As in the 2003 article, there was great individual variability in inferred rankings of the risk comparisons. However, exposure to the risk comparisons did not reduce risk estimates significantly (while raising benefit estimates), and Conflict-Claim respondents found the risk of the hypothetical factory less acceptable than No-Conflict respondents. Results suggest that neither risk comparisons nor risk acceptability claims are automatically anathema to audiences, but they may have tiny or unintended effects on audience judgments about risky situations.     

Applying a Health Behavior Theory to Explore the Influence of Information and Experience on Arsenic Risk Representations, Policy Beliefs, and Protective Behavior

The common sense model (CSM) shows how people process information to construct representations, or mental models, that guide responses to health threats. We applied the CSM to understand how people responded to information about arsenic-contaminated well water. Constructs included external information (arsenic level and information use), experience (perceived water quality and arsenic-related health effects), representations, safety judgments, opinions about policies to mitigate environmental arsenic, and protective behavior. Of 649 surveys mailed to private well users with arsenic levels exceeding the maximum contaminant level, 545 (84%) were analyzed. Structural equation modeling quantified CSM relationships. Both external information and experience had substantial effects on behavior. Participants who identified a water problem were more likely to reduce exposure to arsenic. However, about 60% perceived good water quality and 60% safe water. Participants with higher arsenic levels selected higher personal safety thresholds and 20% reported a lower arsenic level than indicated by their well test. These beliefs would support judgments of safe water. A variety of psychological and contextual factors may explain judgments of safe water when information suggested otherwise. Information use had an indirect effect on policy beliefs through understanding environmental causes of arsenic. People need concrete information about environmental risk at both personal and environmental-systems levels to promote a comprehensive understanding and response. The CSM explained responses to arsenic information and may have application to other environmental risks.     

Knowledge and Risk Perception Among Nuclear Power Plant Employees

This is a study of knowledge, risk perception, and attitudes among nuclear power plant employees. A total of 236 persons participated, belonging to 10 different professional groups and working at two Swedish power plants. Job-related radiation risks were judged about average as compared to a number of other risks. On the whole, the participants in the study were satisfied with the measures of safety at work, but there were some exceptions to this rule, especially among those hired for temporary jobs through external contractors. The experience of job-related radiation risks was related to the level of knowledge about radiation and its risks: those who knew less experienced larger risks. General level of anxiety did not correlate with risk perception. The latter was accounted for mainly by perceived radiation risks. Job satisfaction was more strongly related to perceived conventional job risks than to nuclear risks. Risk ratings were related to how subjects defined the concept of risk. Those who stressed consequences as part of their risk definition gave higher risk ratings.     

Perceived risk,emotions, and stress in response to COVID-19: The interplay of media use and partisanship

Relationships between risk perceptions, emotions, and stress are well-documented, as are interconnections between stress, emotion, and media use. During the early COVID-19 pandemic, the public responded psychologically to the threat posed by the pandemic, and frequently utilized media for information and entertainment. However, we lack a comprehensive picture of how perceived risk, emotion, stress, and media affected each other longitudinally during this time. Further, although response to the pandemic was highly politicized, research has yet to address how partisan affiliation moderated relationships between risk, emotion, stress, and media use over time. This three-wave (N = 1021) panel study assessed the interplay of risk, emotion, stress, and media use for Americans with different political affiliations between March and May of 2020. Findings indicate that perceived risk, emotion, and stress at Time 1 predicted media use at Time 2, with predictors varying by type of media. Use of entertainment media and social/mobile media predicted later stress (Time 3), but news consumption did not. Later risk perceptions (Time 3) were not influenced by media use at Time 2. The predictors and consequences of different types of media use were notably different for Republicans and Democrats. In particular, risk perceptions predicted greater news use among Democrats but greater entertainment media use among Republicans. Moreover, social/mobile media use resulted in perceiving the risks of COVID-19 as less serious for Republicans while increasing stress over time for Democrats.     

Managing Wildfire Events: Risk‐Based Decision Making Among a Group of Federal Fire Managers

Managing wildfire events to achieve multiple management objectives involves a high degree of decision complexity and uncertainty, increasing the likelihood that decisions will be informed by experience‐based heuristics triggered by available cues at the time of the decision. The research reported here tests the prevalence of three risk‐based biases among 206 individuals in the USDA Forest Service with authority to choose how to manage a wildfire event (i.e., line officers and incident command personnel). The results indicate that the subjects exhibited loss aversion, choosing the safe option more often when the consequences of the choice were framed as potential gains, but this tendency was less pronounced among those with risk seeking attitudes. The subjects also exhibited discounting, choosing to minimize short‐term over long‐term risk due to a belief that future risk could be controlled, but this tendency was less pronounced among those with more experience. Finally, the subjects, in particular those with more experience, demonstrated a status quo bias, choosing suppression more often when their reported status quo was suppression. The results of this study point to a need to carefully construct the decision process to ensure that the uncertainty and conflicting objectives inherent in wildfire management do not result in the overuse of common heuristics. Individual attitudes toward risk or an agency culture of risk aversion may counterbalance such heuristics, whereas increased experience may lead to overconfident intuitive judgments and a failure to incorporate new and relevant information into the decision.     

Industry-Dominated Science Advisory Boards Are Perceived To Be Legitimate…But Only When They Recommend More Stringent Risk Management Policies

In 2017, the US Environmental Protection Agency (EPA) was criticized for two controversial directives that restricted the eligibility of academic scientists to serve on the agency's key science advisory boards (SABs). The EPA portrayed these directives as necessary to ensure the integrity of the SAB. Critics portrayed them as a tactic by the agency to advance a more industry-friendly deregulatory agenda. With this backdrop, this research examined board composition and its effect on the perceived legitimacy of risk management recommendations by the SAB. In an experiment, we presented participants with hypothetical EPA SABs composed of different proportions of academic and industry scientists. We then asked participants to rate their satisfaction with, and the legitimacy of, these boards in light of their decisions in scenarios based on actual EPA SAB deliberations. Participants perceived higher levels of satisfaction and legitimacy when SABs made more stringent risk management recommendations. While SABs dominated by industry scientists were perceived to be more strongly motivated to protect business interests, we found no effect of board composition on perceptions of satisfaction and legitimacy. These results are consistent with prior research on decision quality that suggests people use normative outcomes as a heuristic for assessing the quality of deliberations. Moreover, these results suggest that members of the public are supportive of federal SABs regardless of their composition, but only if they take actions that are consistent with normative expectations.     

Worry and Risk Perception

Risk perception is sometimes measured by means of judgments about worry, sometimes as perceived risk more directly. However, perceived level of risk calls for a more intellectual judgment and worry tends to refer to emotional reactions. These two are therefore not the same and need not be strongly correlated. Results reported here show that perceived risk and worry are indeed weakly correlated, both for generalized worry and for more specific measures of worry matched with the same hazard as risk ratings. A distinction is suggested between cognitive, abstract hazards and concrete, sensory hazards, with implications for the worry-perceived risk relationship. It was furthermore found by means of cluster analysis that there were groups of subject displaying different dynamics of risk and worry.     

Public Perceptions of Regulatory Costs,Their Uncertainty and Interindividual Distribution

Public perceptions of both risks and regulatory costs shape rational regulatory choices. Despite decades of risk perception studies, this article is the first on regulatory cost perceptions. A survey of 744 U.S. residents probed: (1) How knowledgeable are laypeople about regulatory costs incurred to reduce risks? (2) Do laypeople see official estimates of cost and benefit (lives saved) as accurate? (3) (How) do preferences for hypothetical regulations change when mean‐preserving spreads of uncertainty replace certain cost or benefit? and (4) (How) do preferences change when unequal interindividual distributions of hypothetical regulatory costs replace equal distributions? Respondents overestimated costs of regulatory compliance, while assuming agencies underestimate costs. Most assumed agency estimates of benefits are accurate; a third believed both cost and benefit estimates are accurate. Cost and benefit estimates presented without uncertainty were slightly preferred to those surrounded by “narrow uncertainty” (a range of costs or lives entirely within a personally‐calibrated zone without clear acceptance or rejection of tradeoffs). Certain estimates were more preferred than “wide uncertainty” (a range of agency estimates extending beyond these personal bounds, thus posing a gamble between favored and unacceptable tradeoffs), particularly for costs as opposed to benefits (but even for costs a quarter of respondents preferred wide uncertainty to certainty). Agency‐acknowledged uncertainty in general elicited mixed judgments of honesty and trustworthiness. People preferred egalitarian distributions of regulatory costs, despite skewed actual cost distributions, and preferred progressive cost distributions (the rich pay a greater than proportional share) to regressive ones. Efficient and socially responsive regulations require disclosure of much more information about regulatory costs and risks.     

Flu,Risks, and Videotape: Escalating Fear and Avoidance

While extensive risk perception research has focused on emotions, cognitions, and behavior at static points in time, less attention has been paid to how these variables might change over time. This study assesses how negative affect, threat beliefs, perceived risk, and intended avoidance behavior change over the course of an escalating biological disaster. A scenario simulation methodology was used that presents respondents with a video simulation of a 15‐day series of local news reports to immerse respondents in the developing details of the disaster. Systemic manipulation of the virus's causal origin (terrorist attack, medical lab accident, unknown) and the respondent's proximity to the virus (local vs. opposite coast) allowed us to investigate the dynamics of public response. The unfolding scenario was presented in discrete episodes, allowing responses to be tracked over the episodes. The sample includes 600 respondents equally split by sex and by location, with half in the Washington, DC area, and half in the Los Angeles area. The results showed respondents’ reactions to the flu epidemic increased as the disaster escalated. More importantly, there was considerable consistency across respondents’ emotional, cognitive, and behavioral responses to the epidemic over the episodes. In addition, the reactions of respondents proximally closer to the epidemic increased more rapidly and with greater intensity than their distant counterparts. Finally, as the flu epidemic escalated, both terrorist and accidental flu releases were perceived as being less risky and were less likely to lead to avoidance behavior compared to the unknown flu release.     

Differences in Perception of Risk Between People Who Have and Have Not Experienced Salmonella Food Poisoning

It is believed that food hygiene precautions in domestic kitchens are an important strategy in efforts to reduce the incidence of sporadic food poisoning, but recent research has shown that people who have suffered food poisoning handle the same types of foods and adopt similar food hygiene precautions in their kitchens to the rest of the population. This suggests the need to examine other factors. A case-control study of sporadic Salmonella food poisoning was conducted to investigate several domestic kitchen risk factors. Measures of perception of risk, knowledge, and control associated with food poisoning in case and control respondents are reported here. It was found that perceived personal risk from food poisoning in the home was less than perceived risk to other people. In contrast, ratings of personal knowledge about food poisoning and personal control over food poisoning in the home were seen to be greater than other people's knowledge and control. There were no differences between the cases and the controls in their ratings of knowledge about food poisoning or their control over food poisoning. However, cases perceived their personal risk from food poisoning to be higher than controls. Both case and control samples exhibited optimistic bias but this was reduced in the case sample, suggesting that experience with food poisoning may reduce optimistic bias.     

Characterising the Perceived Risks and Benefits of Some Health Issues

Previous work on perceived risk, particularly a study by Fischhoff et al. (1978), is critically examined with reference to its applicability to specific health related issues. Judgments were obtained from 159 subjects of 15 health-related items in terms of perceived risk, benefit, and a number of risk characteristics based on the Fischhoff et al. research. In addition, demographic details concerning sex of respondent, seat belt usage, smoking status, and birth order were collected. Using regression analyses it was found that the direction of the risk-benefit relationship was dependent on the issue being judged. Risk was found to be better explained by ratings of likelihood of mishap and likelihood of death as a consequence of mishap. Benefit was poorly explained by the risk characteristics and demographic data. However, subject group characteristics were shown to be important influences on risk and benefit perception in certain situations. The implications of these results for understanding behavioral decisions involving risk in relation to specific activities are discussed.     

Perceived Risks of Conventional and Organic Produce: Pesticides, Pathogens, and Natural Toxins

Public risk perceptions and demand for safer food are important factors shaping agricultural production practices in the United States. Despite documented food safety concerns, little attempt has been made to elicit consumers' subjective risk judgments for a range of food safety hazards or to identify factors most predictive of perceived food safety risks. In this study, over 700 conventional and organic fresh produce buyers in the Boston area were surveyed for their perceived food safety risks. Survey results showed that consumers perceived relatively high risks associated with the consumption and production of conventionally grown produce compared with other public health hazards. For example, conventional and organic food buyers estimated the median annual fatality rate due to pesticide residues on conventionally grown food to be about 50 per million and 200 per million, respectively, which is similar in magnitude to the annual mortality risk from motor vehicle accidents in the United States. Over 90% of survey respondents also perceived a reduction in pesticide residue risk associated with substituting organically grown produce for conventionally grown produce, and nearly 50% perceived a risk reduction due to natural toxins and microbial pathogens. Multiple regression analyses indicate that only a few factors are consistently predictive of higher risk perceptions, including feelings of distrust toward regulatory agencies and the safety of the food supply. A variety of factors were found to be significant predictors of specific categories of food hazards, suggesting that consumers may view food safety risks as dissimilar from one another. Based on study findings, it is recommended that future agricultural policies and risk communication efforts utilize a comparative risk approach that targets a range of food safety hazards.