Bill has a really interesting posting that I'd like to point out.
In earned value and executable code, he describes a policy to measure progress on a project in terms of the percentage of requirements met through executable code. Coding effort (more code, refactored code, whatever) is only progress as more requirements are fulfilled.
This has some very interesting consequences. Writing documentation, modeling UML, etc. doesn't count as progress because no more requirements can be executed successfully. This gets you focused on one of the main tenants of the Manifesto for Agile Software Development (also see "The Agile Manifesto" in Dr. Dobbs): "Working software [is more valuable than] comprehensive documentation." It also means that if you spend the first six months of a year-long project documenting and analyzing, you're not half way done, you're 0% done since you have no working code yet. Yikes!
I like this perspective a lot; it may not be that original, but it's good. However, as the Freakonomics guys would ask, "What are the incentives?" An obvious incentive is to start writing working code. But is that a good idea from day one? Even XP has a week of planning at the beginning of an iteration. A week into an iteration, is your progress really zero? If you take some time to write some tests, do they contribute zero? Does refactoring your code contribute zero?
I've heard Kent say that ideally you could write good software without any tests, since ultimately tests are overhead and don't provide user functionality. Perhaps the same can be said of refactoring, that ideally code is fine the way you instinctively write it the first time. Nevertheless, these efforts do seem necessary in practice. I'm wondering how you justify these efforts when they count as zero progress.
BTW, people and process discusses another good point, that people are more important than process. This has also been captured in the Agile Manifesto: "Individuals and interactions [are more important than] processes and tools."
Anyway, good stuff, go check it out. But consider the consequences as well.