Three Conceptions of Quantified Societal Risk

In several European countries efforts are undertaken, in particular with regard to fixed industrial installations and transport of dangerous substances, to quantify the “societal risk” (SR) of accidents that may cause more than one victim at a time. This article explores the nature of such efforts. SR‐models are essentially ways to structure the distribution of potential social costs of decisions about hazardous activities (e.g., costs of risk reduction, of land use forgone). First, the various ways to describe SR quantitatively, and to set limits to SR will be presented in short. Next, using a scheme developed by Fischhoff and colleagues, the various approaches will be placed in broad categories of reaching acceptable risk decisions: bootstrapping, formal analysis, and professional judgment. Each of the three categories offers a particular appreciation of the risks as ‘external costs’. This has important political implications. In the discussion it is argued that local SR‐limits, by the very nature of SR, should be set in a way that creates consistency with any potential supra‐local interests involved. Second, particular attention is paid to the validity of claims that SR‐limits should reflect a strong risk aversion.