Risk assessments are valuable for identifying, analysing and evaluating risks. However, there seem to be a general tendency to accept the analyses as objective measures of risks, when in reality a fair amount of subjectivity is involved. The primary reason for this subjectivity results from utilising expert judgement. Experts exhibit the same types of biases as lay people with respect to perception of risk, especially when forced to go beyond the limits of their observable expertise. Problems associated with using expert judgements stem from the lack of adequate understanding and treatment of biases. As risk analyses are rational procedures for evaluating risks, values and limitations should be taken into account in a realistic and well documented manner. The contributions from the risk analyses may then be combined with considerations of subjective perceptions of risk and value judgements in the decision making process.
Risk assessments are structured methods for identifying, analysing and evaluating risks, which provide useful support in decision making and the regulatory processes. A risk assessment typically consists of hazard identification and ranking, risk analysis, evaluation and communication. Prior to the assessment phase, it is desirable that risk is handled as "risk as is', while in the assessment and communication phases 'risk as perceived" and value judgements may be considered 1. It is well documented that risk as perceived by the public in many cases deviates from the risk as is, based on objective documentation. However, it is less recognised that experts utilised in risk assessments may introduce subjectivity and biases into the assessment. Risk assessments are typically based on statistics and historical data, but in cases that statistical data do not exist, are not available, or are insufficient, an alternative is to obtain information from experts.
