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It's not special, except that for whatever reason people insist on treating random data as gospel. How long until we cure retinoblastoma? Everyone understands there is no way to produce a meaningful timeline. There are too many inter-related unknowns - various causes, various treatment modalities, varying funding on various fundamental and applied research, no real idea if the final answer is gene therapy, nano-something, chemo, etc. I used to develop software for a defense contractor, and it was pretty waterfall-y. But we built risks in, to an extent. Not by multiplying Sally by 1.3x, Joe by 2.7x or whatever, but you'd chart it all out, showing interconnections (x depends on Y, which depends on Z and Q, which...). And then roughly figure out risks of each of those sub-tasks going long. The idea NOT being you then just multiply by a weight, and ta-da, you have an accurate schedule. The idea is that you have now identified particularly risky chain of events, and now you at least have a chance of managing risk. Every day/week you'd have a risk assessment meeting. Where are we on X, Y, Z. What can we do to get X back on track? Can't, okay, can we we-jigger the dependencies, or is this a hard slip? And so on. I've never seen this done on the commercial side, and it just seems like people are flying blind as a result. "Waterfall is terrible" you reply. Sure. But when you are building an airplane, ya kinda need the 1553B/ARINC bus installed before you install and test the avionics. You can't attach the engines if the wings haven't shown up. You can't redesign the fuselage after the wing builder started building the wings (in general). These are hard, unavoidable dependencies, and changes are often extremely to destructively expensive (hence the endless mind numbing meetings arguing about change control). It is just (IMO) not an unsolved problem, but unsolvable. Too many unknowns results in unpredictability. Your only bet is to manage the risks, adjust as necessary, and accept some things are just unknowable. Agile does that in one way, sophisticated waterfall in another. |