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

In Primavera P6, there are two commonly used activity types: Task Dependent and Resource Dependent. The key difference between them lies in how the software determines the calendar used to calculate the activity’s finish date.

• Task Dependent: P6 uses the Activity Calendar to calculate the finish date.
• Resource Dependent: P6 uses the Resource Calendar to calculate the finish date.

This choice directly impacts the Original Duration and Finish Date of the activity.

Let’s explore this with an example.

• Activity A has a working duration of 10 days.
• The Activity Calendar is set to 7 days/week.

• The activity is assigned to Resource R, who works 5 days/week.

Scenario 1: Task Dependent

• P6 uses the Activity Calendar (7 days/week).
• The activity duration remains 10 calendar days.
• The Finish Date is calculated as 24-Mar-18.

Scenario 2: Resource Dependent

• P6 uses the Resource Calendar (5 days/week).
• The activity duration is extended to 14 calendar days.
• The Finish Date becomes 28-Mar-18.

How P6 Calculates Duration for Resource Dependent Activities

1. When a resource is assigned, P6 initially copies the 10-day duration from the activity to the resource.
2. Using the 5-day workweek of the resource, P6 calculates the Resource Finish Date.

3. This Resource Finish Date is then mirrored to the Activity Finish Date.

4. Finally, P6 uses the 7-day workweek of the activity calendar to recalculate the Activity Duration, resulting in 14 calendar days.