If
- (a medium-sized project with absolutely no change takes X days to complete) and
- (about 25% of requirements change on the average medium project - according to Boehm and others) and
- (lets say the average change, using Boehm's cost of change curve, takes 50 times the effort to change - it might be more, it might be less, depends when it happens)
then
- a medium-sized project with 25% change takes 13.5X days to complete [i.e. X + (.25 * 50) X = X + 12.5X]
Therefore, if we want the shortest project possible then we must prevent change up-front. Even if it takes a bit longer to get it right. If only that were possible.
