2013 is the 10th anniversary of the publication in The Measurable News (March & Summer 2003) of Walt Lipke’s seminal paper Schedule is Different, introducing the concept of Earned Schedule (ES) to the world. This milestone was celebrated at the inaugural Governance and Controls Symposium held in Canberra earlier this month.
One of the notable features around ES has been the amount of hostility towards the concept generated by traditional Earned Value advocates (for an overview of ES see: http://www.earnedschedule.com/).
Everyone who understands EV recognises traditional EV is a very useful cost predictor and also recognises that the traditional SPI and SV calculations lose relevance later in the life of a project and fail completely if the project overruns time (ie, in approximately 80% of projects SPI and SV are less then optimal). To resolve this problem, the traditionalists suggest ‘looking to the CPM schedule’ for answers and decry ES.
Unfortunately, whilst a reliable and accurate CPM schedule is a critical underpinning of any competent EV system, CPM itself is a ‘wildly optimistic process’, see: http://www.mosaicprojects.com.au/Resources_Papers_117.html
One step towards eliminating this destructive debate was achieved this month – at last there is definitive research that validates ES as a technique. A research thesis from the AFIT (US Air Force Institute of Technology) Masters student, Capt Kevin Crumrine compares EVM and Earned Schedule indicators on US DoD ACAT 1 programs (for non-military types – ‘big’ programs). The thesis documents a series of five descriptive statistical tests conducted on the Earned Value data for 64 Acquisition Category (ACAT) I MDAP’s. The research found that Earned Schedule was a more timely predictor of schedule overages than Earned Value Management.
Unfortunately the statistical data did not compare ES with the CPM predictions. The thesis notes ‘One shortcoming to this research is the inability to map the Earned Schedule data to the critical path, but we consider Earned Schedule to be a strong tool for schedule prediction at the summary/contract level.’ The stated reason was ‘Our example produced earned value data no deeper than the Work Breakdown Schedule (WBS) level 3 (ex: WBS Element 1.2.3). The Critical Path data is collected much deeper, as detailed as WBS level 7 (ex: WBS Element 1.2.3.4.5.6.7). This disconnect prevented us from conducting a detailed analysis’
My feeling is the detailed nature of Capt Crumrine’s analysis meant the researcher could not see the ‘wood for the trees’. The only date that really matters on most projects/programs is the completion date! The level the data is collected at does not matter; neither does the activity/work package that that actually drives the final completion. What matters is the end date!!! The fact ES is a better predictor then EV should be 100% accepted and proved by now, and if not this detailed thesis should remove any residual doubts.
What is not proved is does ES provide a more reliable end date than CPM? My assessment outlined in Why Critical Path Scheduling (CPM) is Wildly Optimistic is that ES should be more accurate. Given the mass of data collected by Capt Crumrine it would be a pity if this last step is not applied by a future researcher.
The key role of CPM is (or should be) making the best use of the currently available resources on a project – this is the antitheses of predicting outcomes based on current trends in the way ES does. All that’s needed is another Masters candidate!!
Capt Kevin Crumrine’s thesis, ‘A Comparison of Earned Value Management and Earned Schedule as Schedule Predictors on DoD ACAT I Programs’ is now in the CPM electronic library at http://www.evmlibrary.org/library/Crumrine%20Final%20Thesis.pdf. If you are into analysis it is well worth the read.
Pat Weaver
Lynda Bourne
Aavssitedev's Blog
Sorry Pat, but this whole thing about Walt Lipke having “invented” “earned schedule” is just more PMI marketing BS.
IF Walt had taken the time to do some fundamental research, he would have learned that the entire concept of “Earned Value” evolved from the concept of “earned time” which formed the primary method of incentive payment in the factories of the late 1800’s to 1900’s. While the concept had (and remains!!) well established, even today (in the sweatshops of SE Asia and the maquiladeros of Mexico) it was Frank and Lillian Gilbreth who institutionalized it with their motion and time studies of the 1920’s.
Bottom line- the concept of earned schedule (or earned time) has been around for many, many years now and for PMI to have “honored” Walt for doing nothing more than “reinventing the wheel” is a sad statement for PMI as an organization and Walt as a professional.
My two cents worth!!
BR,
Dr. PDG, Kuala Lumpur, Malaysia
This is the first time I’ve seen Frank and Lillian Gilbreth motion and time studies confused with predicting the likely outcome of a project.
Time and motion study is the scientific study of the conservation of human resources in the search for the most efficient method of doing a task – the ‘one-right-way’. Time study began in the 1880s as a means of wage-rate setting by Frederick W. Taylor and consisted of a wide variety of procedures for determining the amount of time required, under certain standard conditions of measurement, for tasks involving some human activity.
As you state, motion study was developed by Frank B. Gilbreth and Lillian M. Gilbreth and consists of a wide variety of procedures for the description, systematic analysis, and means of improving work methods. It is difficult to separate these two aspects completely. Therefore, the combined term usually refers to all three phases of the activity: method determination, time appraisal, and development of material for the application of these data. Frank and Lillian also broadened scientific management by including the human element, therefore using psychology to gain the cooperation of employees. Motion and time analysis was used to help find a preferential way of doing an element of repetitive work and could assist in effectively managing the activity in a factory.
These ideas certainly underpin modern project management see: The Origins of Modern Project Management, and influence concepts from the WBS onward but beyond that I find it hard to see any connection with the concepts of ES. Perhaps I’m missing something.
I’m not sure where your PMI dig comes from either – Walt’s work was published in the College of Performance Management’s newsletter and the CPM is again free of any tie in with PMI: http://www.mycpm.org/
Thank you for this Information Mr Weaver. I have been using the ES formulas since very long but I did not know its genesis.
Great summary mate, thanks for sharing.
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