In previous posts I covered how to start a new project, how to create the work break-down structure (WBS) and how to create new activities. Today’s post will cover how to establish relationships between two or more tasks.
Many schedules that are built to support federally funded projects are required to meet the GAO’s Schedule Assessment Guide: Best Practices for Project Schedules at a minimum. There are numerous additional specifications put forth by the various federal agencies and their branches, but the GAO guide provides a comprehensive basic framework for building a quality schedule. A major component of a good schedule is that all activities need to be logically linked and sequenced.
By logically linking and sequencing activities you are building a schedule network. For the network to operate properly every activity except for the first & last, needs to have a predecessor and a successor. A predecessor is an activity that needs to come before the next activity due to technical or scope performance requirements. For instance the foundation of a building must be built prior to the floor and walls. The sill plate would be a successor to the foundation walls. The floor would be a predecessor to the walls.
Let’s get started!
First open your project and go to the Activities pane, then click on an activity & show the “Activity Details”.
Figure 1
Once you are able to see the Activity details, go to the Relationships tab. You may prefer to look only at the predecessors, or only at the successors, but for the purposes of this tutorial the Relationships tab will be best.
If you don’t already have the Relationships tab visible, you can find it by right clicking on any other tab & selecting “Customize Activity Details.” Then find “Relationships” in the list of options and use the arrow button to move the Relationships into your current view settings. Click “Apply” once you are done.
Figure 2
Next you should create a few new activities if you don't already have new activities that need to be sequenced. Once you have a few activities that you want to sequence, you can use a few different methods to link them. I will describe two of these methods.
Method 1:
You can link the activities by selecting the activities in the order you would like them in by holding the CTRL button while you individually select the activities in the order that the scope needs to be performed, then right click on the selected activities and click “Link Activities”. See Figure 3.
Figure 3
Once you’ve linked the activities you can review the relationships you’ve just established by looking at the Relationships tab in the details pane at the bottom of your screen. As you can see in Figure 4, “Install Floor Joists” now has “Install Sill Plate” as the predecessor and “Install Subfloor” as the successor.
Figure 4
Method 2:
When a scheduler is building a more complex schedule, instead of the quick method detailed above, I generally recommend assigning relationships from the relationships tab (or the predecessor, or successor tab) and use the "Assign button" (Figure 5), to select the appropriate activity from the list of activities that pops up (Figure 6).
Figure 5
Figure 6
The reason I recommend this method for more complex schedules is that it enables the scheduler to select activities from any area of the schedule and is more precise than relying on selecting a sequence of activities using the Crtl key. Method 2 also allows you to select multiple predecessors or successors for 1 activity.
Note: Scheduling best practices guides put out by various government entities such as National Defense Industrial Association (NDIA), Government Accountability Office (GAO), Department of Energy (DOE) all recommend that most relationships in the network be Finish to Start (FS) relationships. For the examples above I’ve used the standard FS relationship type. This is the relationship type that P6 generally defaults to unless you are linking to/from a milestone. You can check the relationship types that you’ve created in the Relationships tab.
Figure 7
The GAO accepts that there may be a few activities where it makes the most sense to use a Start to Start (SS) relationship, but you should use those only when truly necessary. Future articles will cover the meaning of the various relationship types.
There are many other Scheduling Best Practices relating to establishing relationships between activities and those will be the subject of future articles. I hope you’ve found this basic walkthrough helpful.
Feel free to contact Brite Ideas Project Consulting if you have questions as you move forward learning Primavera P6.
Stay tuned for future posts!
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