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.4. Risk Analysis, Vol. 12, No. 1, 1992 The Interplay of Science, Values, and Experiences Among Scientists Asked to Evaluate the Hazards of Dioxin, Radon, and Environmental Tobacco Smoke George L. Carlo,' Nora L. Lee,' Kelly G. Sund,1 and Sydney D. Pettygrovel Received October 9, 1990; revised 61ay 3, 1991 To investigate the extent to which personal values and experiences among scientists might affect their assessment of risks from dioxin, radon, and environmental tobacco smoke (ETS), we con- ducted an experiment through a telephone survey of 1461 epidemiologists, toxicologists, physi- cians, and general scientists. Each participant was read a vignette designed to reflect the mainstream scientific thinking on one of the three substances. For half of the participants (group A) the substance was named. For the other half (group B), the substance was not named but was identified only as Substance X, Y, or Z. Knowing the name of the substance had little effect on the scientists' evaluation of dioxin, although those who knew the substance to be dioxin were more likely to rate the substance as a serious environmental health hazard (51% vs. 42%, p= 0.062). For radon, those who knew the substance by name were significantly more likely to consider it an environmental health hazard than were those who knew it as substance Z (91% vs. 78%, p<0.001). Participants who knew they were being asked about ETS rather than substance X were significantly more likely to consider the substance an environmental health hazard (88% vs. 66%, p<0.001), to consider the substance a serious environmental health hazard (70% vs. 33%, p<0.001), to believe that background exposure required public health intervention (85% vs. 41%, p<0.001), and to believe that above-background exposure required public health intervention (90% vs. 74%, p<0.001). These findings suggest that values and experiences may be influencing health risk assessments for these substances, and indicate the need for more study of this phenomenon. KEY WORDS: Dioxin; radon; environmental tobacco smoke; decision-making; risk assessment. 1. INTRODUCTION As environmental issues have assumed increasing importance and visibility in Western societies, the influ- ential role of, and the processes followed by, scientists in evaluating environmental hazards are being carefully studied as well. One aspect of the process that has been specifically questioned is the view that scientists are able to make clear distinctions between scientific facts, their personal values, and their experiences in assessing en- vironmental health risks.t'•2? ' Health and Environmental Sciences Group, Ltd., 1225 I Street, NW, Suite 1200, Washington, D.C. 20005. 37 The recently released Regulatory Program of the United States Government stated that risk assessments, at least within the federal government's framework, should be based on science only.(3) Whittemore and others have suggested, however, that when the data are unclear and social and political stakes are high, scientists' interpre- tations of facts are likely to be influenced by their val- ues.t`'-6t The National Academy of Sciences' National Research Council has noted that separation of science and values or policy considerations may not be practi- cal.t'I A recent series of articles in the American Journal of Epidemiology underscored the continuing debate, with one author suggesting that eminent statistician R. A. Fisher selectively interpreted the evidence on smoking 0272-4332/92/0300-0037506.50/1 0 1992 Soctery for Risk Analysis

r Interplay of Science, Values, Experience comprised over 50% of the respondents. The next largest groups of participants were from government and indus- try, about 17% each. The remainder were primarily either private consultants or retired. In comparing respondents within the vignette pairs (e.g., ETS vignette respondents compared to substance X vignette respondents), there were similar representa- tions of disciplines, affiliations, and age categories, as well as similar participation rates, within all vignette pairs. 3.1. Rating the Hazard Four questions regarding hazard or health risk were considered for each substance. The first question was designed to elicit a general response regarding perceived hazard, irrespective of any qualifiers addressing expo- sure level or seriousness of the hazard. The second ques- tion addressed the perceived seriousness of the hazard. Questions three and four differentiated background ex- posure from above-background exposure. Tables II-V present the responses by the specialists to the questions of whether the substance was an envi- ronmental health hazard, how serious of an environmen- tal health hazard, whether background exposure required public health intervention, and whether above-back- ground exposure required public health intervention, re- spectively. Responses by participants for whom the substance was named are compared to responses by par- ticipants for whom the substance was identified only as substance X, Y, or Z. Percentages as well as odds ratios (OR) are given, with ORs near 1.00 suggesting similar replies between the scientists who were read a vignette Table II. Responses to the Question of Whether or Not the Substance Was an Environmental Health Hazard° Response Substance Yes (%) No (°k) OR ProbabilityL Dioxin Named 29.8 70.2 Not named 28.7 71.3 0.95 0.827 Radon Named 90.5 9.5 Not named 78.2 21.8 2.64 <0.001 ETS Named 88.4 11.6 Not named 66.0 34.0 3.93 <0.001 'Percent distributions, odds ratios, and Fisher's exact test probabilities for dioxin, radon, and ETS. 6Two-tailed test. 39 Table 111. Responses to the Question of Rating the Substance as a Serious Environmental Health Hazard° Response Substance Yes (%) No (%) OR Probability° Dioxin Named 51.3 48.7 Not named 42.2 57.8 1.44 0.062 Radon Named 54.6 45.4 Not named 48.6 51.4 1.27 0.216 ETS Named 70.4 29.6 Not named 33.2 66.8 4.78 <0.001 'Percent distributions, odds ratios, and Fisher's exact test probabilities for dioxin, radon, and ETS. 6Two-tailed test. Table IV. Responses to the Question of Whether or Not Background Exposure Required Public Health Intervention' Response Substance Yes (%) No (%) OR Probability" Dioxin Named 32.7 67.3 Not named 34.6 65.4 0.92 0.749 Radon Named 51.5 48.5 Not named 47.3 52.7 1.18 0.449 ); rS Named 84.9 15.1 Not named 40.9 59.1 8.15 <0.001 'Percent distributions, odds ratios and Fisher's exact test probabilities for dioxin, radon, and ETS. bTwo-tailed test. with the substance identified by name and those who were read a generic vignette on substance X, Y, or Z. The probability of different rankings occurring by chance alone was estimated using a two-tailed Fisher's Exact Test. Knowing the substance had little effect on the sci- entists' evaluation of dioxin. Those who knew and who did not know the identity of the substance were similar inrating dioxin as an environmental health hazard, rating background exposures as requiring public health inter- vention and rating above-background exposures as re- quiring public health intervention. Those who knew the substance to be dioxin were more likely to rate the sub- stance as a serious environmental health hazard (Table III, 5 1 % vs. 42%, p=0.062).

Interplay of Science, Values, Experience ards of dioxin, radon, and ETS. Our experiment incorporated three well-known and controversial issues of environmental exposures which have been discussed extensively in both the scientific and popular literature. It was assumed that there was a high level of recognition and awareness among scientists regarding these exposure issues and that mention of the names of the specific substances would trigger certain thought processes as- sociated with the presented scientific facts, values, and personal or professional experiences. Our data show that when scientists were aware they were evaluating dioxin, radon, or ETS, they were more likely to perceive a serious environmental health hazard than when they were read the same facts without the substance being identified (Table III). Conversely, when the substances were not identified, most scientists did not perceive the substance to be a serious environmental health hazard. The findings were strongest for ETS. In our study, the vignette was the main determinant of whether or not a substance was considered hazardous. While the vignettes were designed to represent a fair reading of the mainstream scientific thinking on each issue, it is possible that the ETS vignette was less com- pelling than the vignettes for either dioxin or radon. In other words, the ETS vignette might have given an overly optimistic risk appraisal. Unfortunately, we did not query the participants regarding their perceptions of the accu- racy of the vignettes. We were able, however, to indi- rectly address this question. We attempted to test the validity of the vignettes with respect to their conveying adequate information to accurately describe risk by asking participants to com- pare the risks posed by the substances to the risks posed by driving an automobile. Twenty-two percent (22%) perceived the generic radon vignette as describing a risk similar to, or more serious than, driving a car. Twenty- one percent (21%) of the scientists who were read the generic ETS vignette perceived the substance as carrying a similar risk as, or a more serious risk than, driving a car. Eleven percent (11%) perceived the generic dioxin vignette as describing a risk similar to, or more serious than, driving a car. When the substances were named in the vignettes, the percentage of respondents who con- sidered ETS to be equally as dangerous as, or more dangerous than, driving a car (32.5%) was significantly higher than the percentages that considered either dioxin (9.1%) or radon (9.3%) as such. Nevertheless, it is im- portant to note that both the vignette naming ETS and the generic ETS vignette were considered by over 20% of the scientists to represent a hazard equal to or greater than driving a car, suggesting that the vignettes were quite compelling. 41 Evaluation of the distribution of responses regard- ing seriousness of the hazard for each of the three vi- gnette pairs is also revealing. For all vignettes where the substance was not named, the majority of respondents did not perceive the hazard as serious. Conversely, for all vignettes in which the specific name was mentioned, the majority of the respondents perceived the hazard as serious. The trend was present for dioxin, radon, and ETS. This suggests that the three vignette pairs were consistently compelling in their descriptions of the un- derlying data. Finally, for each generic vignette, similar propor- tions of respondents who were read it believed that they knew the identity of the substance being described, and similar proportions from each group guessed the identity correctly. Overall, it seems unlikely that our findings are ar- tifactual due to fundamental differences in the vignettes. One possible hypothesis for the strength of the ETS results lies in the nature of the risk from ETS. As the work of Slovic et alL has shown,(19) there are several risk qualities that correlate with the level of perceived risk. Individuals are more likely to describe a substance or an activity as risky if the hazard is new, if it may lead to severe consequences, and if it appears as if it could be easily controlled. ETS might fit this description more closely than dioxin or radon. A second possible hypothesis for the strength of the ETS results is the visibility of the issue of cigarette smoking. Most scientists are familiar with the risks of smoking that have been widely publicized. According to the National Research Council, however, ETS is phys- ically and chemically different from the smoke that is inhaled by the smoker,(18) and a recent assessment of the literature by Wynder and Kabat(20) suggests that the data on the human health risks of ETS are equivocal. Using information on cigarette smoking to evaluate the hazard of ETS could therefore result in an elevated estimate of risk. 5. CONCLUSION Our results suggest that scientists' interpretations of scientific facts may be influenced by values and expe- riences. While further research is necessary to clarify the nature of nonscientific influences and the extent and con- sequences of their effect, scientists should note that such influences could lead to biased estimates of environ- mental health risks.

Interplay of Science, Values, Experience Cancer Controversy," American Journal of Epidemiology 133, 416-425 (1991). 9. J. P. Vandenbroucke, "Invited Commentary: How Much Retro- psychology?" American Journal of Epidemiology 133, 426-427 (1991). 10. P. D. Stolley, "Author's Response to 'How Much Retropsychol- ogy?"' American Journal of Epidemiology 133, 428 (1991). 11. H. J. Eysenck, "Were We Really Wrong?" American Journal of Epidemiology 133, 429-433 (1991). 12. J. P. Vandenbroucke, "Invited Commentary: Reply to Eysenck," Ametican Journal of Epidemiology 133, 434 (1991). 13. S. Greenland, "Invited Commentary: Science versus Public Health Action: Those Who Were Wrong Are Still Wrong," American Journal of Epidemiology 133, 435-436 (1991). 14. M. Gladwell, "Scientists Temper Views on Cancer-Causing Po- tential of Dioxin," The Washington Post (May 31, 1990). 15. Universities Associated for Research and Education in Pathology, Ad Hoc Panel on Health Aspects of Polychlorinated Dibenzo-p- dioxins and Polychlorinated Dibenzofurans, "Human Health As- pects of Environmental Exposure to Polychlorinated Dibenzo-p- 43 dioxins and Polychlorinated Dibenzofurans (Universities Associ- ated for Research and Education in Pathology, Inc., Bethesda, Maryland, 1988). 16. U.S. Environmental Protection Agency, Environmental Criteria and Assessment Office, "Health Effects Associated with Indoor Air Pollutants" (October 1987). 17. U.S. Environmental Protection Agency, "Bibliography on Indoor Radon Pollution," (May 1986). 18. National Research Council, Committee on Passive Smoking, Board on Environmental Studies and Toxicology, Environmental To- bacco Smoke: Measuring Fa' posures and Assessing Health Effects (National Academy Press, Washington, D.C., 1986). 19. P. Slovic, B. Fischhoff, and S. Lichenstein, "Facts and Fears: Understanding Perceived Risk," in R. C. Schwing and W. A. Albers, Jr. (eds.), Societal Risk Assessment: How Safe Is Safe Enough? (Plenum Press, New York, 1980), p. 195. 20. E. L. Wynder and G. C. Kabat, "Environmental Tobacco Smoke and Lung Cancer: A Critical Assessment," in H. Kasuga (ed.), Indoor Air Quality (Springer-Verlag, New York, 1990).