
Walt acknowledged the global contribution to the development and furtherance of Earned Schedule over the past 20 years.
He followed with a brief history of how “thinking different” led him to Earned Schedule.
- At the start: successful (and unsuccessful) application of EVM
- Difficulty applying Statistical Quality Control to projects—lack of appropriate data
- Shortfalls in the use of EVM’s SPI
- Functions didn’t fit EVM’s “smooth performance curves” [PV and EV]
- But, the curves could be viewed as a collection of discrete points
- That is, a series of accumulated data—the sums of Planned Value and Earned Value
- A key insight: Earned Value could be mapped to Planned Value to determine the amount of Planned Duration that was earned
- Big question: what to do when the duration earned did not align exactly with a period end
- Trigonometry to the rescue: proof that cost values are proportional to time values
- Deduction of the ES formula: ES = C[omplete] + I[nterpolation], where C equals the periods in which EV >= PVC and I= (EV-PVC)/(PVC+1-PVC)
Walt confirmed the theory with empirical studies. Moving forward, he “built on the new, rather than fighting the old”.
Walt then gave an overview of Earned Schedule’s use.
There are performance indicators and outcome forecasts. There are metrics for project recovery and measurements of schedule adherence. There’s statistical analysis of past performance and estimates of future impacts.
The metrics can be used to manage the current schedule and plan future schedules. As time goes on, you can build an archive of results. You can use them to improve your schedule execution and planning.
Walt noted that there are resources available for learning and applying Earned Schedule. They include study guides, videos, and tools.
Walt’s expectation is that, with greater awareness, application of Earned Schedule will grow.
Final thoughts.
Advanced ES Practices, such as schedule adherence and recovery analysis, will be adopted increasingly. He warned against segregating cost, schedule, and technical performance. And, he noted that control systems outside of EVM are already moving in that direction, but in doing so, they end up creating EVM-like systems.
By contrast, Walt sees EVM plus Earned Schedule continuing to power project control. |