[August 2026] Mary names a paradigm here that I’ve since written a book around, and she got there well before I did. Her claim is that a schedule rolled up from a work breakdown is a hypothesis dressed as a commitment. Chapter 7 of Come Prepared to Die works that axis and leans on this talk to do it, particularly her reading of Sapolsky on Polaris, where PERT turns out to have been a façade built to keep Congress paying. Her Empire State material runs the other way, toward Chapter 8. They had a fixed date, 1 May 1931, because that was when New York leases turned over, and on the day the contract was signed there was no design. The stone went up in 8 months. The job came in 18% under budget. The Empire State build is also the cleanest case I know for scheduling by flow rather than utilisation; I take that up in Utilisation vs Flow. If your plan keeps going nervous on you, the plan is likely the problem, not your team. Working out which one you have is most of the diagnostic I run. If you want this school of thought as a primary document, the 1984 NUMMI team member handbook shows the same thinking written for the factory floor.
A couple of years ago, my former manager David Denton forwarded me a recorded presentation by Mary Poppendieck, a leading Agile software development expert and co-author of the popular book “Leading Lean Software Development: Results Are not the Point.“
Watching the video on the InfoQ website is a bit kludgey and Mary has lots of wonderful details that are worth hearing. So, with Mary’s permission, I’ve had the video transcribed and included her slides in context. I hope that this will make this very useful knowledge easier to find and learn from. Mary, thanks again.
I’ve eschewed block-quote formatting as it made this transcript a little harder to read. I’ve also edited slightly for readability. Otherwise, everything beyond this point is Mary’s work.
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