Fuzzy Concepts in the Analysis of Public Health Risks
Several important concepts encountered in public health risk analysis are not sharp in one sense or another. These concepts are discussed and a view is presented of how they should be treated in a regulatory context. The concepts of an adverse health effect, a highly qualified probability assessor, and an acceptable degree of risk are inherently imprecise. The concept of probability suitable for the purposes of regulatory risk assessment is precisely defined but in general does not result in sharp probability inputs to the probabilistic models required to generate risk estimates; rather, in general the probability inputs are upper and lower probabilities. Furthermore, in general there is secondary uncertainty about what (upper and lower) probabilities should represent the primary uncertainties that give rise to the risk being assessed. Hence, probability assignments need to be elicited from several probability assessors. These two divergences from unique probability assignments are propagated through the probabilistic model to the risk estimates. Hence, risk is a fuzzy concept in the sense that there does not generally exist a unique risk that an adverse event will occur in a given period of time, but rather distributions of upper and lower risk estimates.
KeywordsAdverse Health Effect Probability Assignment Public Health Risk Fuzzy Concept Probability Judgment
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