HomeTroubleshooting@RISK with ProjectsTask Duration Not Changed by RiskProjectAddDelay

6.14. Task Duration Not Changed by RiskProjectAddDelay

Applies to: @RISK 6.x and newer, Professional and Industrial Editions

I added a RiskProjectAddDelay(Tasks!B64, L5, P5) function to my risk register. However, the duration and finish date of the task on row 64 of my Tasks sheet don't seem to be any different.

This is correct. RiskProjectAddDelay doesn't work by extending the duration or finish date of the task that you reference in the function. Rather, it adds a new task after that task. The help file says:

RiskProjectAddDelay(PrecedingTask, DelayLength, DelayCost) adds a new task to a project after PrecedingTask completes. This task has the specified length DelayLength and cost DelayCost. This function is used to add an additional task to the project being simulated only in iterations when a risk event occurs. [emphasis added]

You won't see the effect of RiskProjectAddDelay in any fields of the task you reference in the function. Instead, look at the successor of that task. Its start date will be changed by the amount of the delay, in the iterations where the delay occurs. The successor task's finish date will be changed also, but that change is a little harder to see if you've built any distributions into that successor task.

If the task referenced in the RiskProjectAddDelay function is on the critical path, then the extra delay task will also be on the critical path, and the durations and finish dates of summary tasks will be affected. Even if the referenced task isn't on the critical path, when the delay occurs that may change the critical path so that the referenced task and the delay task are on the critical path during those iterations.

Last edited: 2018-09-13

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