Abstract
We need to describe or deal with uncertainty in risk analysis because risk inherently involves chance or probability. There have been many discussions to define uncertainty in risk analysis. However, different types of uncertainty appear in risk analysis in different ways. Some of them are quantifiable by probabilities, some are not. The appropriate method to characterize the uncertainty, which can be caused by incomplete knowledge or stochastic variability, depends on the kind of its source. The most important result of considering uncertainties in risk analysis is an insight that its consideration gives to the risk assessor. This review presents the basic concepts to deal with uncertainty in risk analysis.
