Introduction to Earned Schedule


Walt Lipke

Oklahoma, USA


Earned Schedule is an extension to Earned Value Management. The method provides considerable capability to project managers for analysis of schedule performance. From the time of the public’s first view of Earned Schedule with the publication of “Schedule is Different” in the March 2003 issue of The Measurable News, its propagation and uptake around the world has been extraordinary. This article will cover the capabilities of the method and challenges encountered, progressing through the significant extensions, to its present status.

Origin of Earned Schedule

Last year, 2013, was the ten year anniversary of Earned Schedule (ES). During its relatively short existence, ES has made a large impact on Earned Value Management (EVM) and project management, as well. Frankly, I have been extremely surprised by its uptake in EVM application and academia, including research.

In my keynote at the 2013 EVM World conference, I recounted the story of how ES came about. In 2002, I was involved with software process improvement in an organization that had nearly achieved Level 5 of the Software Engineering Institute Capability Maturity Model (SEI CMM®). Only one Key Process Area, Defect Prevention (DP), remained to satisfy the achievement of Level 5.

Software organizations were attempting to satisfy DP by applying Statistical Process Control (SPC) to defect counts from the quality process of software development, i.e. inspections and reviews. My belief was that this approach to achieve DP could possibly cause sub-optimization of the development process. This later was shown to be true.

My thought was to use management indicators that encompassed most of the development process. By encompassing the process, the improvement would more generally be beneficial and more likely have positive impact. We were employing EVM; thus, it seemed reasonable to apply SPC to the cost and schedule performance indexes, CPI and SPI, respectively. After all, EVM was used in the project execution phase, generally eighty percent of the effort.

Before much action was taken to investigate this approach, I attended the College of Performance Management (CPM) 2002 spring conference, at which a presentation was given by Quentin Fleming. In his presentation the statistics based research of CPI by Dr. Christensen was discussed. It was fascinating material, and due to the statistical nature of the research it led me to believe I was on the right track with using CPI to satisfy the DP attribute of the CMM®. However, later that evening after some reflection, I realized Mr. Fleming did not mention anything about SPI.

The next morning as I walked through the courtyard of the hotel, I happened to encounter Mr. Fleming, with his suitcase, on his way to checkout and leave the conference. I told him I had attended his presentation and that I was really interested in the statistical testing and study of CPI behavior. I then asked, “Has any comparable research been accomplished for SPI?” Mr. Fleming responded saying, “No there hasn’t. You do know that SPI fails for late performing projects.” …Yes, I knew that, but sometimes you just don’t make the connection. It was then obvious, with the known failure mode of SPI, reliable statistical analysis of the indicator was not possible and therefore the SEI CMM® Level 5 key process area, Defect Prevention, could not be satisfied using the SPI indicator.

This was my dilemma. I needed a reliable schedule indicator for software process improvement; thus, the impetus for creating ES. Originally, ES had a single purpose; i.e., provide a path for achievement of CMM® Level 5. There was no intention for ES to be made available to other EVM practitioners. Only after the schedule indicators from ES proved reliable from several months of prototyping on software projects did I realize that the method held potential for the EVM community. This led to the publication of The Measurable News article “Schedule Is Different” [Lipke, 2003].


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Editor’s note: Second Editions are previously published papers that have continued relevance in today’s project management world, or which were originally published in conference proceedings or in a language other than English. Original publication acknowledged; authors retain copyright. This paper was originally presented at the 8th Annual UT Dallas Project Management Symposium in Richardson, Texas, USA in August 2014. It is republished here with permission of the author and symposium organizers. For more about the annual UT Dallas PM Symposium, click here.

About the Author

Walt-LipkeWalt Lipkeflag-usa

Oklahoma City, OK, USA

Walt Lipke retired in 2005 as deputy chief of the Software Division at Tinker Air Force Base. He has over 35 years of experience in the development, maintenance, and management of software for automated testing of avionics. During his tenure, the division achieved several software process improvement milestones, including the coveted SEI/IEEE award for Software Process Achievement. Mr. Lipke has published several articles and presented at conferences, internationally, on the benefits of software process improvement and the application of earned value management and statistical methods to software projects. He is the creator of the technique Earned Schedule, which extracts schedule information from earned value data.

Mr. Lipke is a graduate of the USA DoD course for Program Managers. He is a professional engineer with a master’s degree in physics, and is a member of the physics honor society, Sigma Pi Sigma (SPS). Lipke achieved distinguished academic honors with the selection to Phi Kappa Phi (FKF). During 2007 Mr. Lipke received the PMI Metrics Specific Interest Group Scholar Award. Also in 2007, he received the PMI Eric Jenett Award for Project Management Excellence for his leadership role and contribution to project management resulting from his creation of the Earned Schedule method. Mr. Lipke was selected for the 2010 Who’s Who in the World. At the 2013 EVM Europe Conference, he received an award in recognition of the creation of Earned Schedule and its influence on project management, EVM, and schedule performance research. Most recently, the College of Performance Management awarded Mr. Lipke the Driessnack Distinguished Service Award, their highest honor, at the 2014 EVM World conference. Walt can be contacted at [email protected].

To view other works by Walt Lipke, visit his author showcase in the PM World Library at http://pmworldlibrary.net/authors/walt-lipke/.