Critical Path Analysis (CPA)

What Is Critical Path Analysis?

Critical path analysis (CPA) is a project management technique that requires mapping out every key task that is necessary to complete a project. It includes identifying the amount of time necessary to finish each activity and the dependencies of each activity on any others.

Also known as the critical path method, CPA is used to set a realistic deadline for a project and to track its progress along the way.

How Critical Path Analysis Works

In the late 1950s, James Kelley of Remington Rand and Morgan Walker of DuPont developed a project management technique called the critical path method (CPM). Earlier versions of their technique were being practiced before then and are said to have contributed to the completion of the Manhattan Project, the secret American defense program to build an atomic bomb in order to end World War II.

Since then, CPA has become a key component in planning and managing projects rationally.

Critical path analysis identifies the sequence of crucial and interdependent steps that comprise a work plan from start to finish. It also identifies non-critical tasks. These may also be important, but if they hit an unexpected snag they will not hold up any other tasks and thus jeopardize the execution of the entire project.

The concept of a critical path recognizes that completion of some tasks in a project is dependent on the completion of other tasks. Some activities cannot start until others are finished. Inevitably, that presents the risk of bottlenecks.

CPA is used widely in industries devoted to extremely complex projects, from aerospace and defense to construction and product development.

How to Use CPA

CPA detects and defines all of the critical and noncritical tasks involved in a work plan and identifies both the minimum and the maximum amount of time associated with each. It also notes those dependencies among activities, and that tells them the amount of float or slack time that can be associated with each in order to arrive at a reasonable overall deadline date.

The project plan must be tracked through the course of a project to make sure every task is on track and no adjustments need to be made. The timeline in a CPA is often expressed as a Gantt chart, a type of bar chart that is designed to illustrate the key dependencies in a complex project.

CPA is used widely in industries devoted to extremely complex projects, from aerospace and defense to construction and product development. Today, project scheduling software is used to automatically calculate dates.