Are not all Lean initiatives about reducing Flow Time (or “Lead Time” as they call it)? p. 97
This is actually interesting in the context of this chapter and the previous ones, and illustrates a good point.
Lean practitioners might take offence if you suggest their work is only about improving flow times or lead times. Another important (if not more important) concept to them is Takt time, which essentially seeks to establish the same task duration at each workcenter, so that as one workcenter finishes a task (or batch), it can immediately be transferred to the next workcenter to be processed.
As they strive to achieve the same “takt time” at each workcenter the flow starts to improve (as you discuss in chapter 5.).
The problem with takt time is that the utilisation factor for each workcenter will approach 1. Which can become a huge problem if there is any variability (i.e the coefficient of variation starts to grow.)
They have to eliminate anything that will cause variability. (This is the reason they are obsessed with waste. They have no choice but to be).
The problem I have with a lot of hard core lean advocates that scoff at ToC is that they don’t seem to understand the underlying principles at work. They just follow the playbook without knowing why.
As they strive to achieve a consistent takt time across all their workcenters and eliminate variability they eventually start seeing good results. Not because they identified the constraint, but because their efforts eventually started to positively impact the constraint, unbeknownst to them, as you pointed out in the first few chapters of the book.
ToC + Lean is a potent mix. Lean on its own will eventually get there but it will take years.
It is that kind of obscurity that leads Agile to wanting to keep teams intact and to totally ignore the Agile Manifesto, which never demanded a single new role, extra responsibility, team structure, additional artefact or one more ceremony. p. 105
That is music to my ears. Couldn’t agree more.