Interpretation of subjective ratings: some fundamental aspects

The use of subjective scores and rankings has become familiar in the context of hazard assessment and risk analysis in health and safety. Less familiar, however, are the mathematical fundamentals that underpin these techniques; a lack in understanding of these fundamentals might lead to the methods being incorrectly applied or to the results being incorrectly interpreted. The paper reviews the fundamental mathematical assumptions made in using subjective measures and the consequences for their interpretation.