MS Project: Branching projects and conditional tasks - how?

Question

I have situations in my projects when the process might go along one of dozen possible paths (sets of tasks) depending on a condition often external to the project, but sometimes linked to one of the previous tasks and milestones.

For example, if by a certain date a certain law is signed, then the project takes one branch after the milestone, if not, it takes another branch with another tasks. Akin to an 'IF' condition in algorithmization, but applied to project management, resulting in multiple critical paths, some of which are interdependent.

Yes, I know that it's possible to create several projects for several conditions, but creating a project version for each permutation of all external conditions would be too tedious. Yet, all the possible paths have to be considered for a really proactive project plan.

I understand that this is somewhat outside the scope of PERT. Is there anything that MS Project can do for me here without any programming/customization?

Answer 1

In addition to Trevor's comments, 3rd party tools provide this functionality.

Check out @Risk or Risk+, or a couple of others that escape me right now.

You might also want to look at Project 2010 Professional (not Standard).

The Active/Inactive tasks feature may give you what you want. See a blog

post I did a while back on the topic: http://blogs.catapultsystems.com/epm/archive/2010/01/26/what-if-analysis-with-microsoft-project-2010.aspx

• Andrew Lavinsky

Blog: http://blogs.catapultsystems.com/epm

Answer 2

Hello Veyda,

If you are using Project 2010, you may find the "inactive" task suits your needs just perfectly.

See:

http://blogs.msdn.com/b/project/archive/2010/06/10/introducing-inactive-tasks-in-project-2010.aspx

I hope this helps.

Julie

Answer 3

I've had similar thoughts concering resources. Apply past performance to models to influence decisions at branch points and/or resource selection.

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Trevor Lowing, PMP http://officetechsupport.wordpress.com/

Answer 4

It would also be very helpful if a simplified form of game theory could be applied to collapse some of the permutations before averaging the remaining ones' float - as a more constructive replacement to very subjective risk/problem management, incorporating risks and mitigative actions into the scope of the project, and not as an external carbuncle on the project schedule's body the way it is now.

But that's just my dreams :)

Answer 5

The biggest downside to doing what you propose is that both logic chains/paths will influence the project float.  If you were willing to accept that you could accomplish this by simple programming as you mentioned:

1. Rename a flag field to "conditional predecessors" and mark any tasks that have conditional successors.
2. Trap the task update event and have it call a custom method to check if the task has conditional successors, read the successors and present the user with an option to break one of the paths. You could also have it read some other external information to determine the path to preserve. Maybe crawn down the rejected path deleting tasks too.

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Trevor Lowing, PMP http://officetechsupport.wordpress.com/