It is useful when reviewing a plan to be able to see what is driving a task or milestone to be at a specific date. This is sometimes expressed as “why the heck is that over there!?”
This article assumes that you have linked your tasks together rather than using a mixture of manually scheduled tasks and constraints.
MS Project provides two key tools to help with this:
The task inspector and
Task path.
Task Inspector
The task inspector shows you which task or constraint is driving the selected task (or milestone) to be the date which it is.
To display the pane click on the Task ribbon / Inspect and chose “inspect task”.
If your task is being driven by another task this will be highlighted (task 6 – Task 6 in this example). This means that you can quickly and easily see which of all the predecessors you will need to affect to change the date of the selected task.
The task inspector pane also allows you to click on the task to jump to it as the task name is a hyperlink. This makes navigating around a large and complex plan easy.
Once you have jumped up the chain to see what is impacting the original task you can retrace your steps by clicking on the “go back” hyperlink. This ability to reverse your tracking through the plan only works whilst you remain in the Inspector pane; as soon as you click into the plan the inspector forgets the “onward” path.
Task Path
The Task Path changes the colour of the related tasks in the Gantt chart. You can chose to change the colour of all predecessors or only the driving predecessor. The same applies to the successors for the selected task. In this instance, we are only interested in the driving predecessors.
Task path allows you to see the entire chain of driving tasks in one action rather than jumping around the plan using the Inspector pane. This can be very powerful when reviewing how to move a milestone or task to a more favourable time.
It does however run into issues when the plan is very long as you you need to see the format change in the Gantt chart.
You can mitigate this drawback by artificially setting a deadline against the task that you are looking at equal to the current finish date. This will cause MS Project to set the driving task chain’s total slack to 0d which will allow you to use the Filter = Critical functionality to hide all elements of the plan which aren’t critical. Obviously, if there are elements of the plan which are on the real critical path these will also be displayed so the Task Path functionality can be used to highlight the chain that you’re interested in. When your analysis work is complete simply remove the artificial deadline.