Keep Your Project On Track By Following the Critical Path Method

Posted on June 25, 2019
Keep Your Project On Track By Following the Critical Path Method

The Critical Path is used to determine a project schedule, while considering all constraints and possible roadblocks that can impact it.

Basically, the method allows project managers to focus attention on the most crucial elements and phases of a project, and make decisions that ensure its success. It has been shown that managers who use the Critical Path are more likely to satisfy project requirements and meet deadlines.

The method was first developed in the 1940s and utilized by international companies and during the Second World War for the Manhattan Project. Today it is common across industries for product development, construction or any major project made up of a series of interdependent activities.

The first step to determining a project’s critical path is to list each separate interdependent task and their deliverables, and then to calculate the least amount of time needed to complete each one. The longest length of time each task can take, while still sticking to the schedule, is also calculated. The project is divided up into its major phases.

From this information, the project manager calculates the earliest dates that each task can be started given the constraints, such as other tasks that must be completed first. Managers then know the latest date that each task can be started and finished without impacting the schedule.

Not every step in a project will be on the Critical Path. Projects also consist of tasks that can be delayed without impacting the project schedule, and are placed on what is called the non-critical path. The length of time that a non-critical task can be delayed is called “float” or “slack”.

It is important to remember that the Critical Path only consists of tasks that have “zero float”. If these tasks are delayed along the way, the project manager knows the deadline is in jeopardy. Using the Critical Path data, they can calculate the amount of time that is going to be added to the project, which is referred to as “critical path drag.”

The more a project manager is aware of restraints and possible “curve balls” to a project, the more accurate the Critical Path will be.

Project managers will need to devote time at the outset of a project to plan the Critical Path. They will find that it pays off in more accurate scheduling and honouring deadlines for clients.


The topic of this article is covered in the curriculum for the Schulich ExecEd course Masters Certificate in Project Management (starting September 12, 2019).

Project Management Certification skills are a new core competency in organizations at all levels. Understanding how all the phases of the project lifecycle fit together benefits projects of any size.