Dave West takes a look at the world views of the Agile and Lean communities and finds them in conflict.
Lean views software development as a process for moving from conception to product. It wants to optimize that process, albeit in a radically different way and with radically different values than traditional (e.g. Taylorism) attempts at optimization.
Agile views software development as a process for building a consensual theory of the world: with an artifact being a byproduct - an expression - of that theory.
Because the fundamental worldviews of the two sides are dramatically different, it is inevitable that there will be conflicts. These conflicts will usually manifest themselves at the level of tools and practices.
If true, then many of us in the community blending Lean and Agile and unaware of the inherent clash in ideals could be making some big mistakes. As an example of a manifestation of this conflict Dave takes the backlog:
Lean looks at the product backlog and sees 'inventory' and 'waste.' Mary Poppendieck is on record suggesting that the product backlog should be eliminated or, at minimum pared to a size more evenly matched to the collective velocity of the teams'.
Agile sees the product backlog as a snapshot view of an emerging theory. Even if that snapshot view is physically manifest as a wall full of story cards, it is not an inventory! The cards on the wall serve as a form of external memory, with each card evoking (recalling to mind) detailed conversations and understandings of how things work.
This article is a must-read if you've been dabbling in both the Lean and Agile worlds.
