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Why is my top float path not the critical path?

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John Reeves
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Why is my top float path not the critical path?  I have a float path that read -164 Total Float with a fnl constraint and completion date of Apr. 6, 2021.  That is a lower Float path than the next path that is -177 with and a fnl constraint of Apr. 25, 2023 but has the check marks for critical path and longesth paths.  Why is the first one ranked above the 2nd one in the Float Path Order?  I really like the float path order chart but don't quite understand it.  My guess is that your first "problem" is more of a problem than your 2nd problem and thus more pressing?  Or perhaps, because there are mixed calendars, the various float though the activities add up to more negative float.


Rodel Marasigan
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Primavera P6 Professional calculates additional float paths in descending order of length, i.e. order of importance.

P6 behavior when calculating multiple critical float paths does not affect how you define critical activities. When you schedule a project, you must choose to define critical activities by a maximum float time or by longest path in the General tab of the Schedule Options dialog box. When you run the scheduler, activities are flagged as critical based on this setting. If you also choose to calculate multiple critical float paths, the float paths are calculated after the project has been scheduled. Critical activities that are not part of a critical float path remain tagged as critical.

Rafael Davila
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Zoltan Palffy
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there are 2 possibilites 

Possibility #1

I would venture to say that the activites on the -164 path are assigned to a 5 days per week calendar and the activites on the -177 path are assigned to a 7 day calendar

Possibilty #2 the pat that leads to the -164 has a constraint on an activity somewhere in that path.

to find the true critical path 

1 .create a new activity code call it my path then give it a code vale of CP for critical path. 

2. make sure that the in predcessor tab window that the boxes for driving and critical are both dsiplayed

3. filter for the last activity

4. look at the predcesor that has both the driving box and the prdecessor box checked.

5. highlight that activity and at the bottom select GOTO

6. keep doing this until you get back to the data date.

7. select edit then select all 

8. Right click and select assign then select activity codes

9. now assign all of thses activity to the my path code and give it the CP value

10. Now add a new filter 


my path equlas CP

now you have the true critical path through the project.