How Big Things Get Done: The Surprising Factors That Determine the Fate of Every Project, from Home Renovations to Space Exploration and Everything In Between

by Bent Flyvbjerg

You start the project by tearing out the existing flooring. And you discover mold in the floorboards. Then you tear out drywall. And you discover old wiring that violates the current building code. Later, your prized granite countertops are delivered. You slip while carrying a slab, breaking it in two. Just like that, your estimate goes up in flames. You are on your way to a major cost overrun. Maybe you think I’m being unreasonable with this illustration. After all, each of the nasty surprises I imagined is unlikely. That is true. But even with a project as simple as a kitchen renovation, the number of possible surprises, each unlikely, is long. Many small probabilities added together equal a large probability that at least some of those nasty surprises will actually come to pass. Your forecast did not account for that. That means your forecast, which seemed perfectly reasonable and reliable, was actually a highly unrealistic things-will-go-according-to-plan best-case scenario, like the best-case scenarios I described in chapter 2. And things almost never go according to plan. On big projects, they don’t even come close.