The SSI Schedule Risk Analysis tool can simulate the realization of identified Risks and Opportunities in a Schedule Risk Assessment. Unlike Duration Uncertainty, which is modeled during every iteration for activities with Best-Case and Worst-Case duration estimates, Risks and Opportunities are treated as discrete events that either occur or do not occur during a given iteration.
This can be visualized as a separate roulette wheel with only two possible outcomes: the event occurs, or the event does not occur. For example, if a Risk has a 25% probability of occurrence, then 25% of the wheel represents “Risk occurs” and 75% represents “Risk does not occur”:
During each simulation iteration, the tool “spins the wheel” on every activity has valid Risk or Opportunity information coded to determine whether the Risk is realized. If the wheel lands on “Risk occurs,” the Risk’s defined schedule impact is applied for that iteration.
Risks and Opportunities can only be modeled during an SRA if a Probability of Occurrence has been defined. The SRA uses this value to determine whether a Risk or Opportunity is realized during each simulation iteration. A Sensitivity Analysis does not require a Probability of Occurrence value.
