Many folks use the terms “efficiency” and “productivity” interchangeably. They are not interchangeable. They are not equivalent. Heck, they’re not even synonyms—even though Thesaurus.com thinks so.

Technically, productivity is a ratio of (good) outputs to inputs; efficiency is the ratio of actual output to standard output. Lean practitioners are typically, and more appropriately, concerned about productivity. As the famous Art Byrne, former CEO of Wiremold, said, “Productivity = Wealth.”

Here’s some often overlooked and misunderstood value-stream mapping math.

The lead time ladder has two levels or “rungs.” The bottom rung is the process or processing rung on which the relevant process time is dropped down. This is usually pretty straightforward... unless there is a split or branch in the material, service, or knowledge flow within the value stream.

For millennia, warriors have taken war trophies to commemorate their victories. They range from the souvenir to war reparations to the just plain gory.

We’re all familiar with the Toyota Production System “house.” You know, the structure schematic with, among other things, the just-in-time and jidoka pillars. Well, sometimes I think it would be more appropriate to refer to the house, any lean house, as a house of pain.

What?! Not great for lean marketing purposes, necessarily. But, there is more than a bit of truth to this notion of lean pain.