Alistair Cockburn's talk the other night was inspiring, thought-provoking, and entertaining. If you have the opportunity to hear him speak, I highly recommend it.
I have been wary of the agile community's current enthusiasm for the Lean literature, as applied to software development. I'm hesitant to trust "manufacturing" as a metaphor for "software development," because I work for a large manufacturing firm. My executive management believe they are experts in efficient manufacturing, and therefore apply those lessons to managing software teams. The agile-to-lean trend gives them permission to make this leap.
The problem comes in attending to the wrong part of the metaphor. Incorrectly applied, it overlooks that developers are knowledge workers, and you are led to believe that they are interchangeable laborers who should specialize on a small task. Easily outsourced, among other things.
But Mr. Cockburn made me realize the right part of the metaphor to apply, the useful part. He said, substitute "unverified decisions" for "inventory," and now you can map your team's process, look for bottlenecks, and improve throughput. When unverified decisions pile up, work is not getting done.
Mr. Cockburn said that different types of bottlenecks mean you need different solutions. He also flouts the strictest adherence to Lean, which would have you remove all waste, and instead suggests spending efficiency to increase throughput. You have too many developers and too few db designers? Let the devs iterate through a bunch of designs and code until they have it really baked, before handing it over to the db designer. Too many analysts and not enough devs? Get the requirements solid, signed off, and thoroughly detailed before giving them to the devs. Too few product owners to tell you which route to build? Build both and let them choose.
Spend your excess efficiency in order to increase the speed of the overall team.
Back to my beef with the manufacturing metaphor. Incorrectly applied, it lets you think waterfall software development makes sense: They give us the specs for a computer, we build it, it gets tested. But the scale is wrong. What a waterfall project actually does is give you the entire order for the DoD's workstation upgrade initiative, and you build 1000 computers before any of them get tested. (A huge backlog of unverified decisions.) Rapid iterations bring you back to building one computer at a time. And Scrum makes the deciding and the verifying nigh simultaneous...
Developer: Purple or green?
Product Owner: Purple.
Developer: 2gigs or 4?
Product Owner: Ooh, 4!
Tester: Oops, hold it, you actually grabbed the 2.
Developer: Whew, good catch.
What I learned from Mr. Cockburn is that the Lean philosophy holds useful lessons for the agile practitioner. Drawing an analogy between writing software and installing chips on a motherboard does not help you, but thinking of your software team as a process comprising different roles, each with their own decisions to verify, can help you increase your team's productivity.