Recently, Cassell Consulting was contacted by a planning engineer who encountered difficulty during critical path analysis. Our resident P6 guru, Ken Wagner, weighed in to clarify best procedures for utilizing multiple critical paths in P6. The following is an edited transcript of their exchange:
Q: “I have a question regarding how to know multiple critical paths.To know first 10 critical paths in Primavera P6. I used to filter (longest Path) to know the first, then delink activity and schedule again (F9) to know the second, and so for rest…
I also used your method:
https://www.cassellconsulting.com/consulting/multiple-float-paths-in-p6.html
but it gives different critical paths from the first method. Which is right?
A: “I sometimes modify my settings based on the analysis I need to do. Sometimes I change the critical path to total float less than or equal to, to a negative number to capture activities that are approaching near critical (note: that this is in hours so for 1 day that would be -24 etc.). I filter for only Task activities (filter out milestones, LOE, WBS Summary, etc.) In group and sort, group by float path and then do a multiple sort criteria for Start, Total float and then the final tie breaker is Activity ID. When you print the report include the columns for Total Float, and free float.
The concept of multiple float paths is a very difficult concept for many people to grasp. So when you add in the idea of near critical (within 2 weeks or -336 hours) the idea of having an activity that in a normal report using the longest path the same activity is not critical but when you look at the near critical it now becomes part of the critical path calculations. That is why it is so important to understand what the float and free float are telling you.
You can also take a normal report with the critical path set to longest path and then filter for a range of float to get the activities. Then sort by total float. This will not give you the individual float paths but it can give you the needed to perform a reasonable analysis.”
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We hope this clarifies the concept of multiple critical paths, and assists our readers in their scheduling endeavors. As ever, feel free to contact us at [email protected] with any questions!
