| Risk Management and Precaution: Insights on the Cautious Use of Evidence Steve E. Hrudey1 and William Leiss2 1Department of Public Health Sciences, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; 2Risk Communication and Public Policy, Haskayne School of Business, University of Calgary, Calgary, Alberta, Canada
Abstract
Risk management, done well, should be inherently precautionary. Adopting an appropriate degree of precaution with respect to feared health and environmental hazards is fundamental to risk management. The real problem is in deciding how precautionary to be in the face of inevitable uncertainties, demanding that we understand the equally inevitable false positives and false negatives from screening evidence. We consider a framework for detection and judgment of evidence of well-characterized hazards, using the concepts of sensitivity, specificity, positive predictive value, and negative predictive value that are well established for medical diagnosis. Our confidence in predicting the likelihood of a true danger inevitably will be poor for rare hazards because of the predominance of false positives ; failing to detect a true danger is less likely because false negatives must be rarer than the danger itself. Because most controversial environmental hazards arise infrequently, this truth poses a dilemma for risk management. Key words: complacency, false negatives, false positives, futility, positive predictive value, zero risk. Environ Health Perspect 111:1577-1581 (2003) . doi:10.1289/ehp.6224 available via http://dx.doi.org/ [Online 10 June 2003]
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