Construction Metaphor Doesn't Work for Me

Matisse has an interesting post, Software is like Building Construction. He talks about iterative design and the interdependencies of people with deliverables as being common to construction and software.

In my opinion, he's not all wrong, but he's not all right. I agree that there are plenty of design-build firms who wait until the last possible moment to cement the design before building. When we remodeled our house, we used an iterative process, and yes, we incorporated the things we'd learned from earlier in the project to the later phases.

But the place where I believe the metaphor falls down is the cementing of design and the use of people. In construction, plumbers don't do electricity, electricians don't do carpentry, and none of tradespeople do any top-level design. (The general contractor might, but not the individual plumber or electrician.) In reality, in software projects, any developer can (and does) change the top-level design if things don't fit. The top-level design does not have to be finalized--ever. In fact, the more releases of a software product, the less some level of design is cemented or finalized. And, effective software people know a lot about the rest of the product, not their small piece.

Construction projects can learn from software and software projects can learn from construction. But to me they are very different in nature and the metaphor does not work as a whole.