Slack isn't waste, it's spare capacity or buffering. Shit
happens, so having
room to react, maneuver and adapt when something
unexpected occurs can help protect deadlines (to a degree) and
avoid potential catastophes.
Tom DeMarco refers to this
room as
Slack .
Kent Beck has added a practice
called slack to
Extreme Programming Edition 2
that advocates including some minor tasks in each iteration, which
can be de-scoped if the team falls behind. I've also used slack as
a feature buffer comprising low priority user stories.
In
Lean Development waste is typically any of the
following:
- Partially done work
- Extra processes
- Extra features
- Task switching
- Waiting
- Motion
- Defects
