Setting the stage for a new profession
by Francis M. Webster Jr., PMP
Out of the chaos of war came the orderliness of project management.
This is PMI's 30th year. Articles will appear this year in PM Network dealing with the profession of project management and in PMI Today dealing with the history of PMI®. This particular article focuses on key events and conditions tha preceded Modern Project Management. If, in reading any of these articles, you find something that varies from your understanding of the historical facts, please communicate them to the PMI Publishing Division, along with supporting evidence, complete citations, and, if possible, a copy of corroborating documents.
The Developing Milieu
World War II was over and the world was recovering from the shortages created by the conflict. The world was also trying to assimilate new knowledge generated as a result of seeking the competitive edge during the war years. Probably the most awesome developments of the time were the atomic bomb and nuclear power. Not only did these pose critical questions for society, they also required massive projects to conduct the research, perform tests, and create the infrastructure necessary to produce the materials required to make nuclear power a reality. These projects required gigantic efforts and coordination. The difficulty of carrying on these projects was compounded by the necessity to perform much of them within the constraints of top security. The magnitude of projects at the onset of the Nuclear Age surely generated an interest in developing better ways to manage the work.
Francis M. Webster Jr., Ph.D., PMP, is a Fellow of the Project Management Institute and acts as PMI Historian. For many years he was PMI's editor-in-chief. Longtime members of the Institute know he was also the voice behind PM Network's “Olde Curmudgeon.”
During the war small groups of scientists where called upon to develop better ways of conducting warfare. Notable was a small project to develop a better methodology for locating German U-boats. Mathematics was used to develop optimum search patterns. New mathematics (exponential smoothing) developed to forecast the location of a warplane to coincide with the time an explosive shell would reach it, which became more necessary and challenging as plane speeds and maneuverability increased. Linear programming, which would later become the underlying methodology for the development work that ultimately led to the Critical Path Method (CPM), was also being developed. Out of these and similar efforts grew the new profession of Operations Research/Management Science. The successes gave legitimacy to the use of scientific methodologies to develop better management tools.
Also out of the war effort grew a need for greater computational capabilities. Mechanical devices were invented to aid in the development of gunnery tables for conventional artillery. Other devices were invented to aim antiaircraft guns to defend against the new aerial warfare. Advances were being made in electronics that made possible an invention that might be considered more awesome than the atomic bomb—the computer. First came analog computers, then digital computers with greatly increased accuracy and flexibility. The Eniac was the first digital computer, leading to the Univac, then to the families of IBM and others’ computers.
Thus, came a whole new perspective from which to consider the management of projects. And from this perspective a train of thought was developing, probably in the late 1940s and early 1950s, for considering the scheduling of projects. The details in this era have not been thoroughly researched and probably few if any of the researchers/academicians involved are still active today. My best guess is that some of them were mathematicians interested in graph theory. This is conjecture based on the similarity of graph theory concepts to the graphic concepts underlying what came on the scene as PERT and CPM. Nevertheless, conversations with some of the key people involved suggest that there was a small cadre of academicians and managers who were concerned with the project scheduling problem and were talking among themselves and with some key industry and government leaders.
Another technique that appears to have influenced developments in project scheduling—Line of Balance—was developed by the Naval Special Projects Office in 1951 and approved in its present form in 1962 [Kane, 1964,“Origin of CPM and PERT,” in Wattel, Ed., Network Scheduling and Control Systems, pp. 40-42, Hofstra]. Others give first credit for the development of Line of Balance to the Goodyear Tire and Rubber Co., under the direction of George E. Fouch. Whoever was first, the “Line of Balance” (LOB) method was actually developed to manage small-lot production contracts, apparently on military contracts. LOB employed a flowchart (network diagram) to describe all the steps necessary to produce one unit of a product. This diagram was presented on a timescaled chart to indicate the time required for each step and, by implication, what the total lead time was for producing one part. By combining this information with a cumulative delivery schedule and a bar chart showing progress on all operations, it was easy to show actual production status for each process compared to what was required to be on schedule. The U.S. Department of Defense actively used LOB as late as the 1970s, with adaptations for managing projects.
These are some of the key events and conditions that created a fertile environment for early developments in Modern Project Management.
Developing the Tools and Practices
In the early 1950s there was considerable discussion of how to improve the performance of projects. A few academicians and practitioners were discussing both theoretical and practical approaches to understand projects and their scheduling. While these efforts were largely uncoordinated, they resulted in at least five different development efforts.
The most publicized effort was PERT (Program Evaluation and Review Technique), which was developed to manage the Polaris Missile Weapons System Program [Malcolm, Rosenbloom, Clark, and Fazar, 1959, “Application of a Technique for Research and Development Program Evaluation,” The Journal of the Operations Research Society of America, Vol. 7, pp. 646-669]. The purpose of PERT was to analyze existing plans to determine the probability that a key event would occur per schedule. It involved three time estimates to assess the uncertainties associated with the duration of each activity. It was “event oriented,” as there was less concern about the work content than with its completion. PERT used a graphical network language similar to “activity-on-the-arrow” (AOA). Each event was given a numerical identity. A pair of these numbers, “i-j,” was used to identify the logical relationships between events.
A concurrent effort with duPont and Univac led to the development of the “Critical-Path Planning and Scheduling System” (CPPS) [Kelley and Walker, 1959, “Critical-Path Planning and Scheduling,” Proceedings of the Eastern Joint Computer Conference, pp. 160-173]. CPPS used linear programming to find the least-cost schedule required to reduce project duration, i.e., the optimum time-cost tradeoff. It received considerable publicity, though less than PERT. CPPS was developed to better plan and manage the construction of new, and maintenance of existing, chemical plants. It used “activity-on-the-arrow” graphical notation and “i-j” identification notation, but was work-oriented; that is, it focused on accomplishing the work needed to get from “i” to “j.” Significant improvements were reported in project performance but practitioners resisted the effort required to estimate two times and two costs (to define the time-cost tradeoff curve) for each. In addition, there were very few computers at the time capable of processing the large linear programming matrices required for practical size projects. Thus, it was not suitable for widespread use. Kelley and Walker joined Mauchly (one of the developers of the Eniac) and simplified the technique by using only one time estimate. This modification became known as CPM.
Another effort by the Air Force Systems Command at Wright-Patterson Air Force Base resulted in a system called “PEI:’ which was similar to CPM except for the network diagramming technique. Each real activity was uniquely identified by its own “i” and “j” while the relationships between activities were portrayed by dummy activities. No two real activities were joined except with a dummy in between. Thus, the total number of activities, real and dummy, necessary to portray a given plan was much greater in PEP than for PERT or CPM.
Meanwhile, efforts at Stanford University resulted in “SPRED” a comparable technique [Fondahl, August 1968, “Let's Scrap the Arrow Diagram, Western Construction]. This effort was aimed at developing a better way to describe and schedule construction projects. It relied on the more common flowchart used in industrial engineering and general systems analysis. The graphical notation became known as “activity-on-the-node” (AON) diagramming and the identification notation focused on the activity rather than on its end points. The calculations involved were the same as in CPM. A very similar, independent development was underway by a professor in France.
With less publicity, a major effort to improve the practices of project management was underway at Wright-Patterson Air Force Base. Gen. Bernard Schriever, commanding general of the Air Force Systems Command, the command responsible for a large number of projects to develop new weapons for the Air Force, introduced the concept of identifying one person to be responsible for a project—perhaps the first formal use of the term “Project Manager.”
Other developments were also in progress at this time. IBM was trying to understand the nature of projects [Norden, March 1960, “On the Anatomy of Development Projects,” IRE Transactions on Engineering Management, pp. 34-42]. Paul Gaddis was looking at team approaches to accomplishing projects [Gaddis, 1959, H arvard Business Review]. And the publicity about all of these efforts was creating a broader interest in the concepts and techniques.
Due to the publicity and training in PERT provided by the U.S. Department of Defense and others, it became the popular system, especially in defense-related industries. PERT gravitated to CPM as users became less enamored with the three time estimates. All of these were based on using directed graphs, now known as project network diagrams (PNDs), as the basic language of planning. People soon referred to PERT charts, CPM charts, precedence charts, and logic diagrams, both as if they were all the same and as if they were drastically different. Soon the distinctions between the computational techniques became fuzzy as practitioners and academicians used the terms differently and interchangeably. The ambiguity persists today, leading to confusion as to what technique, as well as what form of network diagramming, is intended.
THESE WERE THE CONDITIONS that led a few people to conclude that something had to be done to bring some order to the developments in project management and learn the best ways to apply the techniques.
Reader Service Number 5093
April 1999 PM Network