finding a truer longest path in Primavera P6

It’s become generally accepted across many industries using Primavera P6 that identifying and tracking a project’s Longest Path is THE best method to keep your project’s deadline in sight. And we’ve discussed that here on the blog before – that a project’s Critical Path identified as the Longest Path, rather than the path where Total Float equals 0, provides the clearest Critical Path.

Primavera P6 provides you with these 2 options when displaying your Critical Path on the Gantt Chart:

  1. Either display the path of 0 Total Float, or
  2. Display the Longest Path.

There are built-in Filters that can filter your project’s activities in these 2 ways as well.

And in case we’ve forgotten, Oracle Primavera defines ‘Longest Path’ as the string of directly related activities that comprise the longest path from the data date to the last activity in the schedule. It calculates this via a process that follows driving relationships through the project.

However, as you’ll see in the video below, Primavera P6’s built-in Longest Path isn’t always true….but it can get truer through the use of Primavera P6’s ‘Multiple Float Paths’ tool. Please have a watch to find out how to get a truer Longest Path in Primavera P6.



Hi, it’s Michael Lepage from Plan Academy, coming at you with another great Primavera P6 training tutorial. We are out to train you on Primavera P6 and to help you understand all the internal workings of Oracle’s project management software.

Today, we are going to be going in-depth on longest past. Now we have talked quite a bit on our blog and other videos about how in construction and large industry projects, we should be looking at the longest path as our true critical path. Construction scheduling experts out there that this is the new standard and this going to give us the more accurate, a more accurate view of our critical path.

We know that when we are in Primavera, we can go into the Schedule Options and we can turn on the longest option path here, define critical activities as longest path. Great, go ahead and reschedule our projects. Having done that we want to look at the results, what is the longest path of the project?

With that, will go up here to the Filters area and will turn on the longest path filter. We think we’re done. There we go. Here’s our longest path through the project, our most critical path. But I’m questioning your right now whether this is in fact the longest fact, what is being displayed.

Let me show you a couple of areas where we have some difficulties. First thing is, look at these activities here. These are level of effort activities.

When we say longest path through the project, we really want the path where there are no delays between activities, where free flow between activities is really zero. If we have level of effort activities in there, these are not true work activities, true driving work activities. You probably know that level of efforts are summary activities.

So really, should level of efforts be in our longest path? No, they should not. We have a problem there with the critical path, longest path filter displaying level of effort activities.

Let’s come down here and have a look at this area of the project, right here. You can also see that we have some overlapping activities. Once again, we want in our longest path to show the longest path of continuous activities with no overlapping or delays between them.

What is happening here? Why do we have overlapping activities? I can see that there is a finish-to-finish relationship here. Again, we don’t believe that these results should be showing up in the filter. How do we get a true longest path out of Primavera? Well, I’m about to show you.

Let’s go back into our Scheduled options and let’s go and check out the Advanced tab. Now using this advanced option feature P6 the calculating multiple float paths. We can actually get a truer longest path, the ones that filter out the problem issues that we just talked about. If we turn this on and choose these options here, calculate multiple paths using Free Float and simply define the final activity in the project here. We can come up with a truer critical path.

Why is it that I choose Free Float? Let me show you. If I flip over to the Primavera documentation, you see here, it says, “Free float. Choose this option to define critical float paths based on longest path.” That’s what we are after in this case. We are going to use Free Float option here. Having said that, let’s go ahead and close this. Go ahead and reschedule the project.

Great. When you are working with float paths, there are a couple of things you need to do. First thing, we are going to add a couple of extra columns. I’ve added these extra columns, these are columns specific to float paths, float path and Float Path order, so I’ve added those two.

Secondly, what we want to do is go back into our Filters and simply turn-off any filters that we may have on. Float Path will have a value of one, two, three, four, five and up to the number of float paths that we’ve generated. I did ten. But we really only want to look at the first one. What we are going to do is create a filter, where we filter out activities that have value of one for Float Path.

I’ve got that filter built already. Here it is. Although, I’ve called it Float Path 1-3. If we have a look at it, it just says flip path is within the range of one to one or you could set this to ‘is equal to one’. That works great.

Will turn that on. Now were filtering on float path, where float path is equal to one. Now, first thing you want to notice is in our result, we no longer have longest path activities. Those guys are gone. If I scroll this over a little bit, so that you can see a little bit more on what’s going on and total float path, the critical path. Here we go. It starts here.

You are going to see that I no longer have overlapping activities so I really have a true float path, a true critical path, a true longest path, where the activities are totally continuous one after the other.

That’s my tip for you today. Use multiple float paths to get a true longest path out of Oracle Primavera. Hope this has been helpful. Leave me a comment. Let me know what you like or didn’t like about this video. I hope to see you next time. Have a great day.