Statistical Distributions of Health Risks

This study deals with the imprecision associated with estimating the risk of health effects due to environmental causes. The major thrust revolves around the notion that the calculation of statistical risk, itself a probability, contains significant imprecision because of the cascade of error through the computations on which the risk, or probability of contracting a disease, is based. The cascade or risk is an old problem in mathematics and physics, and the conventional issues involving round-off, truncation and related measurement errors are not discussed here. The potential inadequacy of the model by which risk is calculated, the inherent variability in the stochastic processes by which the disease mechanism or initiator is transported down-gradient, and the variability inherent in varying levels of human sensitivity are of more concern. These all conspire to develop a distribution of risk rather than a scalar value, and policy-makers must deal with this distribution in a rational and consistent way. Some suggestions are offered for managing this problem.