There are many types of distributions, the most common of which is the normal distribution; however, the normal distribution is not very useful for the purposes of risk quantification as it requires the standard deviation or variance to be specified as an input which is typically not possible within the context of a risk workshop.
The two most commonly used distributions for risk quantification, therefore, are triangular and discrete. These distributions are appropriate for different types of risks, and the necessary inputs can be more readily identified by risk workshop participants. Triangular and discrete distributions are discussed in detail below.