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Adding a Dependency to Primavera P6

Dependencies (predecessor and successor activities) are crucial to project plans.

In this article, you will learn how to add dependencies to a Primavera P6 plan with automatically scheduled dates.

One of the real values of a project and portfolio management (PPM) application is the ability to define dependencies between activities – for instance, Task B cannot start until Task A is completed. With these dependencies built into your project, you can make a more realistic and more robust plan.

Like other PPM applications, Primavera P6 allows you to define predecessors and successors for a given activity. This article will show you how.

  1. We’ll start with a simple project plan with a single Start Milestone. Need to learn how to add a Start Milestone to a project? Our article on that topic is linked.

    Simple P6 plan with only a Start Milestone.

  2. Before we add any dependencies, we need to make sure our project is subject to automatic scheduling. Otherwise, the dependencies we define will not (automatically) affect the schedule. From the ribbon, go to Tools > Schedule > Options... > General, and ensure that the option for Schedule automatically when a change affects dates is checked. Then hit Close.

    Turning on automatic scheduling in Primavera P6.

  3. With that done, we next add a second activity to our project. Right-click on the Start Milestone and choose Add.

    Adding a new activity to our Primavera P6 plan.

  4. This inserts a new activity beneath the Start Milestone, with a default duration of 5 days.

    The new activity, with a 5-day default duration.

  5. Now, we need to identify "Project kickoff" as a predecessor activity to "New Activity." First, select the "New Activity" row if it is not already selected. We will define its predecessor from the Details window – if this is not displaying, toggle it from View > Show on Bottom > Details. Once there, go to the Predecessors tab and click the Assign button.

    Locating the Predecessors tab of the Details window for our New Activity.

  6. In the dialog box that appears, you will see both activities in our project. Selecting "Project kickoff," you will see the green Assign button activate. Click it to commit the dependency.

    Setting up the dependency between Project kickoff and New Activity.

  7. Several things have happened. First, the dependency is recorded in the Predecessors tab of the Details window:

    Our new dependency is shown in the Details window.

  8. Also, if you change the start date of "Project kickoff," it will also change the start date of "New Activity."

    The New Activity start date changes as the Project kickoff start date changes.

  9. Finally, the chart to the right of your activity list shows an arrow between the two activities.

    An arrow represents the dependency on the chart.

Needless to say, activity dependencies can become very complex in large projects. But this article has given the basic skills you need to define predecessors in a Primavera P6 plan.