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Driving predecesssors

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Bill OBrien
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How is it possible to identify which predecessor is driving an activity. ie How can you tell from viewing the list of predecessors in the predecessor window which has zero float??

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Rafael Davila
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From the following link you can download a sample file where you can explore the Task Drivers view error in MS Project.

http://rapidshare.com/files/274278953/Bug_on_drivers_pane.zip

If you find why, let me know, maybe we can get rid of this fly.

Best regards,
Rafael
Rafael Davila
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Joined: 1 Mar 2004
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I don’t believe float will tell you if a predecessor is driving or not. A predecessor might be part of another chain that is defining its float, if in another chain that happens to be in the critical path it will show 0 float but it will not necessarily be the driver of the successor in question.

You might have two activities in tandem none critical, both with the same non 0 float, and the predecessor might be the driver, zero float is not a requirement for a predecessor to be driving.

By the way the Task Drivers view from the Toolbar in MS Project 2007 is unreliable and seems to have bugs. I changed a non driving 0 lag SF relationship to FF and then it became driving, no way.

From : http://scheduleanalyzer.com/sa_long_theory.htm

Slack

We are not surprised that you have never hear of the term “slack” as it concerns a CPM relationship. That is because we just made it up! This doesn’t mean that this is a trivial matter, it just proves that you can’t invent a thing until you first invent another thing (or you can’t get there from here.)

Slack is the amount of ‘unused’ time difference between the predecessor and the successor activities. This slack value has nothing to do with the float values or either of the two activities that it relates. It merely indicates how close each predecessor is to becoming the driving relationship for the successor activity.

... Hum, I heard of the term "slack" as related to CPM over 30 years ago, it was on one of the fisrt editions of the book Project Management with CPM and Pert by Moder and Phillips, latter renamed to Project Management With Cpm, Pert and Precedence Diagramming by Joseph J. Moder, Cecil R. Phillips, Edward W. Davis

Remember that Total (Activity) Float as per traditional CPM jorgon is renamed as Total (Task) Slack by MS Project, therefore maybe relationship slack shall be renamed to be relationsip float as per MS Project unique jorgon. Unconsistency rules our trade.

Best regards,
Rafael
Bill OBrien
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Joined: 19 Feb 2007
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Ok cheers
Alexandre Faulx-B...
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Bill,
you’re right: in MSP 2k, 2002, 2003, you should write a VBA macro to get the information you want; if you are able to retrieve the driving link from the predecessor and the task float, you will satisfy your need
Alexandre
Bill OBrien
User offline. Last seen 1 year 42 weeks ago. Offline
Joined: 19 Feb 2007
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I am using MSP2000 version. Are you saying that this function is not available in this version?
Alexandre Faulx-B...
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Bill,
this is a new feature in MSP2007
Alexandre