On the Role of Subjective Probabilities in Fire Risk Management Studies

If risk management studies in fire protection are to be implemented on a quantitative basis, it becomes necessary to estimate probability loss models for each risk management alternative. While actuarial data may exist for quantifying the risk of situations similar to the alternatives under review, there are usually enough di fferences or envi ronmenta1 uncerta i nt i es that direct subst itut ion is considered to be i nappropri ate, and dependency on subjectively assessed probability loss models is a reality to be recognized. In our opini on, a common percept ion by pract it ioners in fi re protect i on engineering is that subjective probabilities are "just guesses " and not to be used in any serious or rigorous fire protection risk management study. This paper points out that subjective probability assessments are valid representations of knowledge, and we seek to communicate guidelines from decision analysis for generating subjective probabilities within fire ris