Ch 3. Model and data limitations: the sources and implications of epistemic uncertainty

Chapter 2 focused entirely on aleatory uncertainty. This is the uncertainty that arises out of the randomness of the hazard itself, and also, possibly, out of the responses to the hazard outcome. That chapter chased this uncertainty through the footprint function and a loss operator to arrive at an Exceedance Probability (EP) curve. Such a structured approach (e.g. as opposed to a purely statistical approach) was motivated by the need to evaluate different interventions, for choosing between different actions; and by the possibility of non-stationarity in the boundary conditions, on policy-relevant time-scales measured in decades.