Is There a Role for Qualitative Risk Assessment?
This work is incremental, offering a technique to enhance risk assessment in domains where objective numerical data is scarce, such as chemical safety evaluation.
The paper addresses the limitations of purely numerical risk assessments by proposing a method that incorporates qualitative and weak quantitative characterizations, demonstrated through a prototype system for predicting carcinogenic risk of new chemicals.
Classically, risk is characterized by a point value probability indicating the likelihood of occurrence of an adverse effect. However, there are domains where the attainability of objective numerical risk characterizations is increasingly being questioned. This paper reviews the arguments in favour of extending classical techniques of risk assessment to incorporate meaningful qualitative and weak quantitative risk characterizations. A technique in which linguistic uncertainty terms are defined in terms of patterns of argument is then proposed. The technique is demonstrated using a prototype computer-based system for predicting the carcinogenic risk due to novel chemical compounds.