Scholars Award: Three Methodological Rules in Risk Assessment

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

At the first or hazard-identification stage of risk assessment, there are frequent controversies over supposed risks associated with various agents - such as particular cell phones, pharmaceuticals, or pesticides. Often conclusions of different scientists, published concurrently in refereed journals, contradict each other regarding the existence of some hazard. While politics or agenda-driven funding sources help explain some conflicts, many appear to arise from methodological disagreements over the causal inferences used to interpret epidemiological statistics and risk data. For at least 10 years, these conflicts have been known as "the epidemiology wars" - one focal point of which is disagreement over 3 methodological rules used to assess risk data. These are the epidemiological-evidence rule (EER), according to which causal inferences about harm require (human) epidemiological data, not merely animal or laboratory data; the statistical-significance rule (SSR), according to which the null or no-effect hypothesis ought to be rejected only if there is statistically significant evidence of harm (p < or = 0.05); and the relative-risk rule (RRR), according to which hazard identification (alleging that some agent has caused a given harm) requires evidence of a relative risk of at least 2. Intellectual Merit. The project - evaluating how effective accepting, rejecting, or amending these 3 methodological rules is, in advancing various cognitive goals of epidemiological risk assessment - has 7 main objectives. These are (1) to provide a methodological overview of strengths of EER, SSR, and RRR; (2) to use (1) to assess each rule's methodological weaknesses; (3) to evaluate different factual circumstances on which using/not using each rule is contingent; (4) to assess which cognitive and practical goals are served by accepting/rejecting each rule; (5) to determine which epidemiological demarcation criteria are served by accepting/ rejecting each rule; (6) to investigate which amendments to each rule might fit different epidemiological demarcation criteria, factual circumstances, and cognitive goals; and (7) to use reviewers' criticisms to revise the project findings. In explicating methodological rules (e.g., Doppelt, Laudan, Schmaus), causal explanation (e.g., Cartwright, Glymour, Suppes), philosophy of statistics and experimental inference (e.g., Mayo), especially in medicine (e.g., Clouser, Kyburg, Schaffner) - philosophers of science have done superb basic research. However, this project is needed because no philosophers of science have investigated EER, SSR, and RRR, relative either to epidemiological risk assessment or to its demarcation criteria, factual context, and cognitive goals. PI qualifications include degrees in mathematics and in philosophy of science; 3 post-docs (economics, biology, hydrogeology); 3 decades of grants/publications on risk-assessment methods (but not on the project's 3 methodological rules); and coauthoring many US National Academy of Sciences risk-assessment studies, including the 1996 classic, Understanding Risk. Broader Impact. In many years on US EPA's Science Advisory Board, the PI has evaluated epidemiological methods/rules used in scores of risk assessments, especially for pesticides. Key project methods (bibliographical research, conceptual analysis, assessing methodological assumptions, evaluating consequences) were used in the PI's earlier grants/publications. Examining EER, SSR, and RRR in conflicting risk assessments (of 32 organophosphate pesticides, done for 2006 US re-registration) - with which the PI is familiar, because of Science Advisory Board work - the PI will assess 13 hypotheses about how demarcation criteria, factual contexts, and cognitive goals help explain conflicts over methodological rules.