Risk assessment: ‘numbers' and ‘values’

Risk assessment has two components, which I shall term ‘numbers' and ‘values'. ‘Numbers' refer to the estimation of the likelihood that an adverse event will occur in a stated period of time. The methods are mathematical and statistical. ‘Values' refer to the processes of attaching a value to the risk and deciding what should be done about it. Benefits are weighed against costs in what is largely a moral enterprise. Maden (2003, this issue) asks ‘why all the fuss?’ about standardised risk assessment. My fuss is largely about the ‘values', not so much about the ‘numbers'.