Guild of Project Controls: Compendium | Roles | Assessment | Certifications | Membership

Tips on using this forum..

(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?

(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.

multiple activities affected by a single risk

2 replies [Last post]
Mark Higgins
User offline. Last seen 4 years 11 weeks ago. Offline
Joined: 27 Jan 2017
Posts: 2
Groups: None

Good evening,

I have been approached by a PM that I support who has asked a question of which i am unsure how to answer.

The question is about applying a single risk against multiple schedule activities

would the best approach be to breakdown the over arching risk into smaller multiple risks, and apply individual probability and 3 point estimate values on a task by task basis.

The risk is based around Human Resource availability


any assistance would be greatly received





Rafael Davila
User offline. Last seen 2 hours 32 min ago. Offline
Joined: 1 Mar 2004
Posts: 5011

Definitively resource availability might not be deterministic, this is an excellent question.

If using Spider Project I would suggest using the 3 scenarios approach to model different resource availability profiles [optimistic, pessimistic and probable] using Time or Activity resource production. 

 photo 3scenarios_zps4i9xzjdu.jpg

This method does not have many of the limitations Monte Carlo models do have and can be implemented using your CPM software without the need for specialized Risk software.

The following SPERT Excel Templates might help you get the distribution curves, with little modification you can get the cumulative % distributions.  Statistical PERT Normal Edition uses ratio scale multipliers to modify the standard deviation of a normal curve. This lets Statistical PERT work with any bell-shaped uncertainty that can be estimated using a 3-point estimate for minimum, maximum and most likely outcomes.

 photo CumS01_zpsel6afgpl.jpg

 photo CumS03_zpsdm3w7nmt.jpg

Mike Testro
User offline. Last seen 20 weeks 6 days ago. Offline
Joined: 14 Dec 2005
Posts: 4407

Hi Mark - Welcome to Planning Planet

There are many types of risk that affect multiple tasks - weather is typicle.

If there is likely to be a shortgae of labour then put a cap on the number expected to be deployed and the end date will extend accordingly.

Best regards

Mike Testro