Microsoft Project as a simple method to find out which tasks are driving the ‘Start Date’ for a selected task. These are called “Task Drivers.” In other words, predecessor tasks that affect successor tasks.
Here’s how to find the task driver for a selected task:
1. Click on any task that has predecessors
2. Click in the “Track” menu button in the tool bar
3. Choose “See what is driving the start date of a task”
4. A panel appears at the left, showing the tasks that drive the selected on
Here, you can see that “Task 1a” drives “Task 2”, even though “Task 1b” is also a predecessor. Task 1a is a “Task Driver” to Task 2.