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A Brief History of CPM Scheduling in Construction

Critical path method (CPM) scheduling has become an essential tool for construction project managers to ensure timely project completion. It is a technique used to schedule a project by defining the activities, their duration, and their dependencies. CPM scheduling has a rich history in the construction industry, and in this blog post, we will take a look at how it evolved over time.

Origins of CPM scheduling

CPM scheduling technique was first developed in the late 1950s by two separate teams working on two different projects. The first team was led by Morgan R. Walker and E. W. Kelley Jr. at DuPont, who developed the technique to schedule maintenance projects at the company's chemical plants. The second team was led by James E. Kelley Jr. and Winter H. Orr at Remington Rand Univac, who developed the technique for the U.S. Navy's Polaris missile program.

Early adoption in construction

The construction industry began adopting CPM scheduling in the early 1960s, with the first major project being the construction of the Humber Bridge in the UK. The bridge, which spans the Humber estuary and connects Yorkshire and Lincolnshire, was one of the largest construction projects of its time. CPM scheduling was used to manage the project, which was completed on time and within budget.

Humber Bridge under construction

In the United States, CPM scheduling was first used in the construction of the Indianapolis Motor Speedway in 1961. The technique was used to manage the construction of the track and facilities for the Indianapolis 500 race, which is one of the most significant events in American motorsports.

Development of computer-based CPM scheduling

In the 1970s, the development of computer technology allowed for the creation of computer-based CPM scheduling software. This software made it easier for project managers to create and manage project schedules, reducing the risk of errors and improving the accuracy of the schedules. It also allowed managers to run different versions of the schedule to plan for different scenarios and risks.

One of the first computer-based CPM scheduling software programs was Primavera Systems, which was developed in the mid-1980s. The software quickly became popular in the construction industry, and it is still widely used today.

Advancements in CPM scheduling

Over the years, CPM scheduling has undergone several advancements. One significant advancement is the integration of building information modeling (BIM) with CPM scheduling. BIM is a 3D digital representation of a building or structure that can be used to visualize and analyze various aspects of the project. When it is linked to a schedule it is referred to as a 4D BIM model.

Another significant advancement is the use of mobile devices and cloud-based software, which has made it easier for project managers to access and update project schedules in real-time.


The critical path method (CPM) scheduling has come a long way since its inception in the late 1950s. It has become an essential tool for construction project managers to ensure timely project completion. The technique has evolved from a manual process to computer-based software, and it has been integrated with other technologies, such as BIM and cloud-based software. As the construction industry continues to evolve, it is likely that CPM scheduling will continue to advance as well, helping project managers to plan and execute projects more efficiently.

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