Physics 2, Business Administration 2

I think Maciej gets it half-right in his comment on the space shuttle disaster.

Physics 2, Business Administration 0
“When a program agrees to spend less money or accelerate a schedule beyond what the engineers and program managers think is reasonable, a small amount of overall risk is added. These little pieces of risk add up until managers are no longer aware of the total program risk, and are, in fact, gambling.
Columbia Accident Investigation Report, pp 139
One of the most sobering conclusions of the Shuttle accident report is that the Columbia was an exact replay of the Challenger – the same false confidence, the same scheduling and funding pressure, the same lack of attention to an intermittent problem whose causes were never understood. There’s even the same badly-designed briefing slide, failing to convey the urgency the engineering team feels, and the same old Edward Tufte on hand to point it out, once the investigation gets into full swing.

Maciej is absolutely right that business managers have no business setting schedules and making risk assessments over the heads of the technical folk.
But he’s wrong to say that the answer is to get rid of every last PHB. Geeks should have the sole voice only on projects whose primary goal is technical.
Where a project has a non-technical objective, the decisions about requirements and scope need to be made by people with domain expertise.
XP gets it right, here, I think. The technical people are the only people who can set the schedule for technical work and assess technical risks. If you ignore this principle, you are living in a world of delusion and inviting disaster.
The people who understand the business objectives should have say over what the project should do and when they think it’s done.
Tangra’s comments about the gaps in the Deanspace program highlight the flaws in a project driven by geeks, for non-geek users. The Deanspace documentation explains the technical features and schedule of the project, but still lack some of the documentation — and features– that are needed to make campaign activist group successful.
This isn’t a fatal flaw — Deanspace is a volunteer project that needs more volunteers to fill in this gap. But it does point out that you need customer input to be effective with a projec that has non-technical goals.