Earned Schedule Application


to Projects with Performance Interruption



By Walt Lipke

Oklahoma, USA


The interruption of project execution by stop work and down time conditions impact the values computed for Earned Schedule indicators. The distorted values, in turn, have the potential to affect management decisions. To address the problem, a special calculation method for handling these conditions is presented and examined using four sets of notional data. Comparisons of the computed values from special and normal ES calculation methods indicate significant improvement using the special calculations. 


Earned Schedule (ES) is an extension to Earned Value Management (EVM) providing the capability of schedule analysis.[1] ES was introduced in 2003 by my article “Schedule Is Different” [Lipke, 2003]. From 2003 until the present much has happened. For those applying ES, the method is broadly considered to be a significant advancement to the practice of EVM. ES has propagated across the world, including the USA, Australia, United Kingdom, Belgium, Spain, Canada, India, Japan and other countries, as well. It is being used across all industries applying EVM for all sizes of projects. Furthermore, the method is being used in research, instructed in several universities, and is included in recent project management texts and the newer EVM analysis tools. Recently, standards and guides have been published by the Project Management Institute and the International Standards Organization, including Earned Schedule in the practice of EVM. Earned Schedule is no longer a novel idea; it is accepted practice.

The measure of ES has provided schedule analysis and forecasting capability to those using EVM, previously not believed possible. Parallel to forecasting final cost using EVM measures, ES facilitates a simple calculation for the forecasting of project duration and completion dates. Furthermore, it has been shown that the forecasting is enhanced through the application of statistical methods [Lipke, 2009]. Additionally, another measure has been derived from ES, “Schedule Adherence” [Lipke, 2009]. This measure, in turn, has provided the capability to perform detailed analysis, yielding identification of process constraints and impediments and specific tasks having the likelihood of future rework. Recently, additional analysis methods, derived from the idea of schedule adherence, have been developed for forecasting rework cost and analyzing schedule duration impacts [Lipke, 2019; Lipke, Jan 2020; Lipke, Apr 2020]. These advancements are freely available for study and exploration through the literature and calculation tools at the Earned Schedule website, www.earnedschedule.com.

Broadly speaking, the ES methods have proven to perform very well. However, there are conditions during execution that can cause error in the calculated values for the ES indicators and duration forecasts. These conditions are the following:

  • Down Time – periods within the schedule where no work is scheduled
  • Stop Work – periods during execution where management has halted performance

However, it is worthy to note that even when down time and work stop conditions are encountered, normal ES calculations converge to the correct duration forecast and the final schedule variance result. The remainder of this paper will discuss the method of handling the two conditions and describe the results from application to notional data.


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Editor’s note: A version of this article was published in the April 2011 issue of PM World Today (Vol XIII, Issue IV), titled, “Earned Schedule Application to Small Projects.” The article presented methods for handling project interruptions. Due to the world-wide Covid-19 virus pandemic many projects have experienced execution work stoppages. The on-line journal PM World Today has ceased publishing, making the original article difficult to obtain. This article re-creates the calculation methods needed for schedule performance management, when project performance is interrupted.

How to cite this paper: How to cite this paper: Lipke, W. (2022). Earned Schedule Application to Projects with Performance Interruption; PM World Journal, Vol. XI, Issue III, March. Available online at https://pmworldlibrary.net/wp-content/uploads/2022/03/pmwj115-Mar2022-Lipke-earned-schedule-application-to-projects-with-performance-interruption.pdf

About the Author

Walt Lipke

Oklahoma City, USA


 Walt Lipke retired from federal service with over 35 years of experience in the development, maintenance, and management of software for automated testing of avionics. As a manager, a career highlight was his organization’s winning of the Software Engineering Institute / Institute of Electrical and Electronics Engineers award for Software Process Achievement. 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). He is the creator of Earned Schedule (ES). Mr. Lipke has published over ninety articles on the method, as well as two books, Earned Schedule and Earned Schedule Plus. Additionally, he has presented research on ES and its schedule performance analysis methods at several conferences in the United States, and internationally.

For his contribution to project control, the practice of EVM, and the creation of ES, Mr. Lipke has received several awards: 2007 Project Management Institute Metrics Specific Interest Group Scholar Award; 2007 Project Management Institute Eric Jenett Award for Project Management Excellence; 2013 Earned Value Management Europe Award; 2014 College of Performance Management Driessnack Distinguished Service Award; In 2017, the Australian Project Governance and Control Symposium honored Mr. Lipke by establishing the annual Walt Lipke Project Governance and Control Excellence Award. The award is made for excellence in research, expanding knowledge of the management and governance of projects, programs, and portfolios in Australasia.

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

[1] The article assumes a reasonable understanding of EVM and ES. If more explanation of EVM is desired see [Humphreys, 2002]. For the fundamentals of ES see [Lipke, 2009].