ABSTRACT
The public and policy makers often have difficulty in assessing the risks from extreme events, and deciding on the appropriate measures to ameliorate these risks. This can lead to worst-case thinking, probability neglect, risk aversion, and avoidance of the notion of acceptable risk. This can also result in a frightened public, costly policy outcomes, and wasteful expenditures. An illustrative case study is a risk assessment to remove 14 fig trees from an iconic street in Newcastle because the risks were judged too high. Yet the trees had survived many storms and were undamaged. However, an arborist consultant calculated that the risk of harm was 1 in 19.8 per tree per year – so walking down that street was 10 times more dangerous than downhill skiing! Other examples relate to terrorism and climate change. A common denominator is the seemingly inability of the community and public officials to grasp the notion of risk and probabilities. The paper will describe how decision metrics often involve probabilistic thinking by public officials, and how best to communicate this type of information in a manner more easily grasped by the community and public officials.
