Existence Risks

Words on this page that have been underlined and italicized can be found in the glossary on the bottom of the page.

Overview

An existence risk is an activity which may or may not occur. By default:

All activities start out with an existence probability of 100%, meaning they will occur in every iteration during the simulation
When an existence probability of less than 100% is entered, the duration is zeroed out for those iterations that it's sampled as not occurring

Example	Option 1	Option 2
Schedule resubmittal	Including in the duration range results in an overly pessimistic distribution on the submittal activity	Successor activity to schedule submittal with 0 day duration, existence probability <100%
Risk of encountering contaminated soil during excavation	Including as a risk impact may conflate weather modeling	Insert activity with 0 day duration, existence probability <100%

Designating Existence Risks

Click the Ranging
icon.
Click the View button above the top list and choose Duration and Cost.
Scroll to the desired activity.
Enter a value less than 100% in the Existence Probability column.

Tip

To turn on the Existence Probability column, see Customizing Columns.

Glossary

Existence Probability: the percent of iterations an activity will occur. When it occurs, the activity's duration is sampled from its range. When it doesn't occur, its duration is zeroed out for that iteration.

Next Steps

Add risks to the risk register

Run a simulation