Skip to main content

The Rules of Lean Project Management: Part 5

Rolling the Waves

My little series on the rules of Lean Project Management was supposed to end with Rule No. 4 (Humans, Humans, Humans) discussed in this blog last October. However, I will now expand my set of “rules” following Lean Project Management specialist Hal Macomber’s enlightening comments on my series in his blog (

Hal observed that I left out three important principles underlying Lean PM, namely: make commitments at the last responsible moment, PDCA everything (Deming Wheel), and produce deliverables in small batch sizes of one or single-piece flow. I did not cover those, since I believed they were not unique to Lean Project Management. However Lean gives them a special slant, certainly worth presenting as additional rules or principles. To the three extra principles proposed by Hal, I will also add, in retrospect, another one: the single tasking of multiple tasks.

So let’s continue with Rule number 5 of 8 (….until we find other ones!): The Roll the Waves rule.

Hal notices in his blog that (as last planners – my addition) you should make your choices and commitments at the last responsible moment». He, and other Lean practitioners, noticed a habit on projects to lock down requirements early, to get material on order early, to grab resources early. These steps rarely help and usually add waste to the project. Further, we lose options when we act early.

I would somewhat equate this principle of making commitments when we are more certain of possible outcomes with the practice of Rolling Wave Planning alluded to in the PMBoK and very well presented by Gregory D. Githens in his excellent white paper, Rolling Wave Project Planning ( Good project managers and their team understand that it is useless to plan in detail the whole of a project when one does not have the results of the current project phase or stage necessary to elaborate clearly the next phase. For example, it is quite a waste of effort to detail the development phase of a new product before we have a clear definition of its concept and design criteria. It is also presumptuous to commit oneself on the design of a building’s foundations when the results of required geotechnical studies are not yet available.

On one of the projects I helped plan for an architecture firm, the project client ask me to be more specific on things that were planned to happen three years later; he wanted to discuss details about this period. I had to tell him then that this was useless to discuss these points further while nobody had made precise commitments about the feasibility study phase we were about to begin; these commitments were still impossible to make then, because we had yet to have his permission to enter the future project site to assess initial conditions.

The Rolling Wave Planning principles are very simple: take commitments and detail your planning for the work about to begin, for which you have all the information necessary to take proper action (very low uncertainty). These are “work packages” that you can commit to deliver with a high level of certainty for a given budget and schedule. For the work to accomplish in a later phase, most often requiring as input the results of the work packages you are working on, you should stay away from too much detail, since you do not really know what will be needed then. Rather, you can present this latter part of the project as a set of “planning packages” that will be revisited and detailed only when appropriate – when we have a clearer understanding of what has to be done and what CAN be done.

Rule No. 5 of LPM – Make your choices and commitments (promises) at the last responsible moment. Make them in the form of work packages that will deliver the desired results anticipated with a high degree of certainty….

…Roll the waves: plan the work, execute the work, learn and adapt, plan the work, execute the work, learn and adapt, plan the work, execute the work…succeed

Comments (5)