On the subject of project schedule and completion forecasting



11 March 2023

Ref: Weaver, P. (2023). Earned Schedule – the First 20 Years; PM World Journal, Vol. XII, Issue III, March. Available online at https://pmworldjournal.com/wp-content/uploads/2023/03/pmwj127-Mar2023-Weaver-Earned-schedule-the-first-20-years.pdf

Dear Editor,

I really appreciated Patrick Weaver’s detailed 20-year history of Earned Schedule (ES) and related footnote references in the March 2023 issue of the PMWJ.

However, while Patrick reaffirms the fact that before the advent of ES there was “no accepted methodology for adjusting future work durations or resource requirements based on performance to date,” and “the assumption that all future work will go as planned tends to make the results from a CPM update process a very optimistic assessment of the likely project completion,” nevertheless a range of Best Case, Most Likely & Worst Case projections could still be developed from Critical Path scheduling and Earned Value schedule data.

While my formulas may not be pro forma or de rigueur ES, for many years I have forecast project completion dates based on CPM & EVM data, using the baseline calendar schedule data – i.e. rather than the monetary value – of the project’s reported PV & EV variance status.  This is captured in my latest IPPSTAT template, illustrated in Figure 1.

Figure 1

NOTE: A constraint of my calendar day computation is that it is based on a 7-day week.

Moreover, to assist Portfolio & Program managers — as well as others who may perhaps not be so intimately familiar with the multitude of EVM acronyms, or the dirty details of the project — fifteen years ago I created another template – illustrated in Figure 2 – (Part A & B) to analyze CPM & EVM data and assess the status and trends (Part C), as well as the verity of estimates by project managers who were reporting to them (Parts D, E & F).


To read entire Letter to the Editor, click here

How to cite this work: Smith, K. F. (2023). On the subject of project schedule and completion forecasting, Letter to the Editor, PM World Journal, Vol. XII, Issue IV, April. Available online at https://pmworldjournal.com/wp-content/uploads/2023/04/pmwj128-Apr2023-Smith-on-project-schedule-forecasting-Letter-to-Editor.pdf