11 - Inference, decisions, monitoring and updating

Summary

Risk assessments are prey to unacknowledged ambiguity and vagueness, as well as the psychological idiosyncracies and social contexts of those involved. Chapters 1 and 4 outlined the factors that lead people to colour their judgements, including such things as the level of personal control, as well as the visibility and dreadfulness of the outcome. These frailties lead to a number of identifiable symptoms including insensitivity to sample size and overconfidence (Fischhoff et al. 1981, 1982, Fischhoff 1995, Morgan et al. 1996).

Risk-based decisions should weight the probability of an incorrect decision by the consequences of an error. The preceding chapters outline techniques that can be used to build models that serve to protect stakeholders, risk analysts, experts and managers against some of the worst excesses of their own psychologies and contexts.

Once the analytical phase of the risk assessment is complete, the task remains to interpret the results, decide a course of action and design feedback mechanisms that will ensure that decision-making capability improves through time. This chapter outlines a number of methods that have particular utility for monitoring environmental systems, providing information to revise assumptions and models and to support decisions.

Monitoring and power

Monitoring is sampling and analysis to determine compliance with a standard or deviation from a target or prediction. It may be undertaken to gauge the effectiveness of policy or legislation, to test model assumptions, or to validate predictions.