Conflicts between two cultures: implications for epidemiologic researchers in communicating with policy-makers.

Received for publication September 12, 2000, and accepted for publication May 31, 2001. From the Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD. Reprint requests to Dr. Genevieve Matanoski, Johns Hopkins Bloomberg School of Public Health, 111 Market Place, Suite 850, Baltimore, MD 21202. During the 1990s policy-makers, including the US Congress, increasingly called for evidence-based decisions on environmental and other policy issues (1, 2). By implication, this appeal implies that scientific evidence has not always played a major role in decisions affecting public health because of gaps in the evidence and even prejudice against public health data as “soft.” Some would now argue that science can and does have an impact on policy decisions. They would place epidemiology as the foundation of public health science. Since epidemiologic data measure risks directly in humans, findings of epidemiologic research are perceived by many as the most relevant indicators of adverse effects in humans. Because of the immediate relevance of human data, epidemiology probably engenders the most commentary and criticism of all the public health sciences. The discussion is fueled by the inability of epidemiologists to “control” their research as toxicologists can control their experiments, and, consequently, the results of observational research are inherently subject to uncertainty and imprecision. Recent debates over acceptable levels of risk for radon, air pollution, mercury, and lead—for which much epidemiologic data are available—exemplify the debate that may arise when major policy decisions are largely driven by epidemiologic data. Discussions and even heated debates about the adequacy and interpretation of scientific evidence are frequent and now inherent to policy debates, seemingly creating a conflict and a gulf between science and policy (3–5). The decision-makers sometimes find it difficult to understand and to use the scientific evidence, especially in the context of the inevitable limitations and uncertainties clouding any scientific evidence. While the recent movement toward evidence-based policy has been positive in its policy implications, it has also led inadvertently to increased distrust of science and scientists on the part of policy-makers who want more from scientific evidence than they believe they are getting. This distrust has spawned conflicts between science and policy which need to be resolved to improve the basis for decision-making. Both disciplines need to expand their efforts to understand their different roles in policy-making. The following presentation will focus only on suggestions for scientists, especially epidemiologists, which may help reduce some of the conflicts. In order to reestablish credibility, scientists must define their roles and the role of science in decision-making and educate the policy-makers regarding these roles. Science alone does not drive policy decisions, it is simply one source of information. Epidemiologists, as well as other public health scientists, need to better understand the role that epidemiologic evidence may assume at a policy level and to learn how to interact with policy-makers. As an initial step, they need to understand the framework for decision-making. Since science and policy often meet over environmental issues, examples of this framework’s use in environmental policy decisions will be highlighted in this presentation.