On the quantitative definition of risk

The purpose of this paper is to provide some suggestions and contributions toward a uniform conceptual/linguistic framework for quantifying and making precise the notion of risk. The concepts and definitions the authors present in this connection have shown themselves to be sturdy and serviceable in practical application to a wide variety of risk situations. They have demonstrated in the courtroom and elsewhere the ability to improve communication and greatly diminish the confusion and controversy that often swirls around public decision making involving risk. They hope therefore with this paper to widen the understanding and adoption of this framework, and to that end adopt a leisurely and tutorial place. In particular, they carefully draw a distinction between ''probability'' and ''frequency.'' Then, using this distinction, they return to the idea of risk, and give a ''second-level'' definition (of risk which generalizes the first-level definition) and is large enough and flexible enough to include at least all the aspects and subtleties of risk that have been encountered in the authors' experience