What is the difference between Activity type: Task Dependent and Resource Dependent in Primavera P6

In Primavera P6, there are 2 popular activity types: Task Dependent and Resource Dependent.

What is the difference between these types?

By choosing the activity type, P6 will select what calendar is used to calculate the finish date of the activity:

• Choose Task Dependent: P6 use Activity calendar
• Choose Resource Dependent: P6 use Resource calendar

It will affect the Original Duration and Finish Date of the activity.

To demonstrate the function above, let’s look at the following example.

Activity A:

• Working duration is 10 days
• Activity Calendar is 7 days / week

• This activity is assigned to resource R working 5 days / week

If we choose Task Dependent, P6 will use Activity Calendar. Then activity duration will be 10 days. Activity Finish Date is 24-Mar-18

If we choose Resource Dependent, P6 will use Resource Calendar. Then activity duration will be 14 days (the process of calculating this duration is explained in below section). Activity Finish Date is 28-Mar-18

When choosing Resource Dependent, the process of calculating Activity Duration:

When we assign resource to activity, P6 copy the value 10 days from activity duration to resource duration. Then it uses 5 days workweek of the resource to calculate Resource Finish Date.

Then P6 will mirror Resource Finish Date to Activity Finish Date. Then it uses 7 days workweek of the activity to calculate Activity Duration.