If asked for an accurate schedule for a large project, offer management two options. 1) Two months spent writing complete product requirements documentation, w

If asked for an accurate schedule for a large project, offer management two options. 1) Two months spent writing complete product requirements documentation, while engineers research and estimate all tasks and sub-tasks. 2) We start right now with the minimal documentation we have, using priorities Marketing has given us and work with Marketing to flesh out the details for every component as we build it. In case 1), you get a schedule in two months. The schedule won't be accurate because it won't be able to anticipate everything. Most likely it won't be able to anticipate how product requirements will change during our lengthy development, and they most certainly will change given that Marketing isn't going to stop talking to customers or thinking of new ideas. But you'll have a schedule. In case 2) I'll guarantee the project will be finished faster and be a better product. You don't get an accurate schedule either, but you also don't lie to yourself that the one you have is accurate.