Risk Assessment: Tools, Techniques, and Their Applications

15.5 Qualitative Risk Assessment

In a simple model of risk assessment, the two factors comprising risk are evaluated. Probability and consequence are analyzed and assigned nonnumerical values. These may include high, medium, low, and intermediate. Values assigned to consequence may include none, undesirable, unacceptable, and effect (no, little, and significant). A simple evaluation tool can be constructed by forming a grid with probability and consequence forming the x- and y-axes. While relatively simple in concept, it has been demonstrated to be useful for decision makers. However, its simplicity limits its functionality for more complex decisions such as modeling and event over time, incorporating several actions with multiple outcomes. In addition, the modeling of uncertainty would be impossibly difficult. So in many cases, a more powerful tool is needed.