P6 Longest Path made up of 16 multiple float paths

Patrick (Robert?),

Would have to see it to be sure, but what you've described is a critical path with 15 short, parallel, returning branches.  These are not particularly uncommon and often won't even be noticed on a typical Critical Path layout.  MFP has simply highlighted them for you.

Example: Framing -> Mechanical Rough-In (5d) & Electrical Rough-In (5d) -> Drywall

The two rough-in activities share a common predecessor, successor, and duration.  They are separate activities mainly because they are separate crews.  With the free float option, MFP creates a new float path for each extra predecessor (after the first one on each activity) that it encounters during the backward pass.  In the example, MFP creates a new float path for the second predecessor of "Drywall."  As a result, one of the rough-in activities will be on Float Path 1, and the other will be on Float Path 2.

IMO, having 15 of these kinds of branches reflects a certain simplification of resource productivity (and pacing) that may or may not be realistic for your project.

Good luck, tom 

1st how are you defining critical ? There whould be a most criticla path meaning the one with the least amount of float.

you can also go to schedule then options then advance and set the specific mumber of critical paths to calculate.

You could also create a new actviity code call it most critical and give it a value MC. Now add that code as a column. Then filter for the last activity in the schedule. Look at the predecessor tab and mighk sure that in the predecessor window that the driving AND critical coumns ares shown.  Now in the predecessor window look for the predcessor that has BOTH boxes critical AND driving checked and clikc on that predecessor. NOw at the bottomof the predecessor window click on GOTO an goto that predecessor. Now keep doing this until you get back to the data date or the start of the project. Now add that MC value to the first activity and thne do a fill down in tha column for the rest of the activities. Now you can filter group and sort on this information.  

All the projects that I review are based on Longest Path as critical. This project is a relatively small that is lump sum resource loaded maily for USACE requirements as far as costs.

As I dig deeper I’m starting to see redundant logic ties that don’t make sense. In my schedule reviews/analysis I’m always curious about multiple paths mainly to see what is creeping up from behind especially when given just the critical path in PDF format. This particular project stood out more than others and I was wanted another opinion as to what this indicates at a quick glance before digging deep. Most projects that I have seen viewing them with the multiple paths schedule option show the longest path broken into maybe 2 to 4 paths at most on average. I do understand that the true longest path lies in path #1 but path #1 in this project consist of 4 activities if I were to filter out the other paths.

Thanks

Patrick,

Your statement, "I do understand that the true longest path lies in path #1...," is based on a misunderstanding of MFP vs. LP analysis.  From what you've described, float paths 1-16 are all equally valid (from a pure logic standpoint), parallel components of the Longest Path.

In general, Float Path #1 from an MFP (FF) analysis will always be a driving path ("the most critical path" according to P6 Help), but one must visually examine the subsequent float paths (in sequence) to find/confirm the first non-driving path.  In the situation you have described, the first non-driving path is Float Path #17.  Unfortunately, P6's Help file does not address this condition and presumes that there is no concurrency/parallelism.

Float Path #1 having only 4 activities in it is a bad sign.  (From your ealier description I was imagining an order of magnitude more than that, like 100.  Then the 15 cases of 1 or 2 concurrent activities wouldn't be much of an issue.)  As described, this schedule has multiple, huge, exact concurrencies.  That smacks of date manipulation, i.e. arbitrarily expanding durations (and sequestering float) to exactly match the time available; OR optimistically compressing durations as needed to meet the time required.  Not good.

you can use software to check for redunat logic

I can email you how to find reduntant logic  

Thanks Zoltan. Can you send me the link concerning redundant logic

Thanks Tom & Zoltan I really do appreciate you wisdom and advice and willingness to share.

no problem

Good luck.