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Relationship Logic Type

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Richard Carpendale
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This question may have been posted before?

Does anyone know of a way to identify Relationship LOGIC TYPE (as distinct from ordinary Relationship Type; FS,SS....)

I have identified 3 logic types (there may be more);

  1. Physical Logic - i.e. can not physically start/finish until predecessor has started / finished 
  2. Strategic Logic - activity sequencing is driven by higher level strategic plan.
  3. Discretionary Logic – Used in the absence of Types 1 or 2, essentially to eliminate dangles.

It is common practice to employ all these Logic Types. However their use is not usually documented. This makes it difficult to review the ongoing impact of type 2 & 3 logic on total float and the critical path.  When reviewing the critical path it is import to know what activities are driven by Type 2, so that a strategic review can be considered. And if activities with Type 3 Logic have diminishing float their logic can be reviewed. This information is vital for the development and maintenance of a realistic Critical Path.

Richard Carpendale 

Replies

Richard Carpendale
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Vladimir, Gary, Mike and Patrick
Thanks for you comments They were very helpful. 

Cheers

Richard Carpendale

Patrick Weaver
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This discussion is very similar to the ideas underpinning Fred Plotnick’s  Relationship Driven CPM.  For a brief overview and links to resources see: http://www.mosaicprojects.com.au/WhitePapers/WP1035_RD-CPM.pdf

Mike Testro
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Joined: 14 Dec 2005
Posts: 4418

Hi Richard

In Asta power project you can also assign different colours and dot / dash lines to different links.

Otherwise you can set up a user ield and just type in the link category.

Best regards

Mike Testro

Gary and Richard,

I think that it is necessary not only to know logic types but to be able to switch on and off certain logic types.

For example to create several sets of soft logic, try them and select the best set to be applied.

For this purpose it is not sufficient to know if the logic is soft or hard, but create custom logic type like soft logic 1, soft logic 2, etc. or use different names like strategic, etc.

Regards,

Vladimir

Gary Whitehead
User offline. Last seen 4 years 47 weeks ago. Offline

Richard,

I tend to use 2 divisions: hard logic (which would be your physical logic, plus other mandatory logic such as H&S requirements) and soft logic (which is everything else)

 

Asta has similar functionality to Spider in terms of ability to assign a category to each logic link. Primavera and MS Project do not. i can't remember how Open Plan handles it.

 

other than this type of functionality, the other common way of noting logic type is via a schedule narative, which should document such things along with any assumptions, productivty norms, resource limitations, etc used in generating the schedule.

It's not common in my experience for this type of document to be kept up to date as the project progresses, though.

 

Agree that this info is vital for optimising your critical path, but if the info isn't readily available, I tend to be able to muddle along fairly well working this out by exception for the critical relationships I am interested in. -A decent planner shouldn't have too much trouble working out what is hard logic and what is soft.

 

Cheers,

 

G

Richard,

in Spider Project you may set any number of dependency types, and then filter, sort, show or hide dependencies basing on custom logic types.

Regards,

Vladimir