Deadlines aren't difficult to hit if you can properly estimate the amount of time required. It sounds like in your case your deadlines are being pushed down fro

Deadlines aren't difficult to hit if you can properly estimate the amount of time required. It sounds like in your case your deadlines are being pushed down from above without any regard to feasibility. Obviously the larger in scope the project, the more likely the deadline is going to slip because more things can go wrong. A good project manager can help anticipate this and mitigate risk.