How to Show Critical Path in MS Project?

In this Microsoft Project tutorial, you will learn what is a ‘Critical Path’ in Project Management terms, and how to show a critical path in an MS Project schedule.

Before we begin the MS Project part, first we will delve a bit deeper to know what is a Critical Path, and its significance when it comes to managing a project.

Table of Contents

• What is a critical path in Project Management?
• Why Critical Path is important in a project?
• How Critical path calculation is done?
• When can a task be critical in a project?
• How to show the Critical Path in an MS Project schedule?
• How can you shorten the critical path?
• How can you change the critical path of a schedule?

What is a ‘Critical Path’ in Project Management?

In Project Management terms, a Critical Path is the longest sequence of tasks that must be completed in order to complete a project. The tasks that comprise the critical path are called Critical activities as any delay in the completion of these activities will affect the completion of the entire project, and thereby affect the project duration.

Why Critical Path is important in a project?

Projects generally consist of multiple activities to be completed in a systematic manner. The interdependency of tasks may lead to multiple paths (sequence of activities) to complete a project. For the Project Manager and key drivers of the project, knowing the critical path is, hence, of paramount importance.

Knowing the critical path facilitates the Project Management team as it helps them to:

• identify task dependency more properly and prepare a better, realistic project schedule by prioritizing tasks
• estimate the project duration more accurately
• allocate critical resources to the appropriate and most deserving activities when there is any scarcity in the project
• understand which tasks are to give more focus for better progress of the project.

How Critical path calculation is done?

MS Project defines critical tasks as tasks that have zero floats or slack. Well, it’s not only MS Project, any scheduling software uses the same principle to define critical tasks. In fact, this is the definition of critical tasks irrespective of the scheduling software you use.

Now, to explain further, we need to understand what is Float or Slack of the tasks in a schedule.

Float or slack is the amount of time a task can be delayed without affecting the total timeline of the project.

The slack of a task can be determined by its early finish and late finish dates. The early finish date of a task is the earliest date by which you can finish your task, and the late finish is the date by which the task can be finished at the latest, without delaying the project finish date.

Hence, for a task,

Float (or, Slack) = (Late finish date) – (Early finish date)

For the tasks on a critical path, the late finish and early finish dates are identical, hence slack (or float) = 0

When can a task be critical in a project?

• It has zero floats or slack
• The task has a Must-start or Must-finish date constraint
• The finish date is equal or greater than its deadline date
• It has an ‘As-late-as-possible’ constraint in a project scheduled from a start date (ALAP)
• It has an ‘As-soon-as-possible’ constraint in a project scheduled from a finish date (ASAP)

How to show the Critical Path in an MS Project schedule?

Microsoft Project is a scheduling software that enables you to schedule the tasks of a project by linking them based on their interdependencies, thereby creating sequences of tasks to complete the project. A project consists of many tasks and there could be multiple ways to complete the project, but the longest sequence is the critical task.

Follow the simple steps to show the critical path in a Microsoft Project (MS Project) schedule are as below:

Step 1: List all the tasks in a project sequentially, and add their individual durations.

Step 2: Add the project start date.

Click OK.

Step 3: Make sure that the tasks in your schedule are Auto-scheduled (not manually scheduled). Keep the option checked at the bottom bar of the MS Project window.

Tip: If you have already created a schedule in MS Project with tasks in manually-scheduled mode, no problem. Just select all the tasks and click on Auto Schedule button in the Task ribbon of the MS Project window.

Step 4: Add Predecessors to the tasks to create the sequences to complete the project. A Gantt Chart will be created in the right pane of the MS Project window.

Step 5: Now click on the Gantt Chart button at the top-left corner and select Tracking Gantt view.

The color of the bars on the right side corresponding to the critical tasks will become red. The color of the non-critical tasks will remain blue.

How can you shorten the critical path?

If you change the duration of any of the critical tasks, the duration of the project will change accordingly. You can try the same in the schedule you have just prepared, to understand the same hands-on.

Shortening the critical path means shortening the project duration. To do this, try the following:

• Try to shorten the tasks on the critical path (i.e. critical tasks) supported by proper logic
• Try to break the critical tasks with a higher duration into subtasks to understand if simultaneous working is possible anywhere
• Check the interdependencies of the tasks and modify them wherever possible
• Schedule overtime for critical tasks to complete them earlier
• Assign additional resources to critical tasks to complete them earlier

How can I change the Critical path of a schedule?

Tip: Critical paths are not constant for a project or a schedule. If you are successful to bring down the duration of the critical path of your project, another path (sequence of tasks to complete the project) can become critical.

Also, when the critical tasks of a schedule are eventually finished, a new sequence of tasks can become critical.

The same can happen if any other sequence (path) of tasks is delayed substantially, as now they become the longest path with zero float for the consisting tasks.