Slack != Waste

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

The practice of slack reduces waste because it helps to avoid partially done user stories. Partially done user stories are waste because they have no business value precisely because they are incomplete.


Tags: agile, extreme programming, slack, lean

posted by Simon Baker @ permalink
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