Fixed Scope And A Deadline Is Grift, Not A Way To Work.

The iron triangle (time, cost, scope) has been around for at least 40 years. The basic idea is that only two of the points can be fixed. Fix all three, and you have a death march. It's not like we don't know that.

Nonetheless, you have clients demanding a death march by specifying both a deadline (which in software, is both time and cost—they track one another) and a fixed scope. They do not do this out of ignorance. They know as a fact that the project will run over if the scope can't vary. They demand the impossible because it's a way to squeeze free work out of you. (They are never penalized in the contract for providing an incorrect scope; rather, you are penalized for being "late.")

This is a scam, plain and simple. It's a way for the client to move 100% of the risk onto your shoulders and to squeeze more work out of you than they're paying for. Why anybody would fall for this particular bit of grift is beyond me, but whole segments of the industry seem willing to volunteer for the gallows.

In software, there are only two arrangements that make sense: (1) Time and materials, and (2) Fix the increment and let (collaborative) scope vary. Everything else is just lambs (that's you) to the slaughter.

I'll add that a fixed scope almost always leads to building something nobody wants. We learn as we work, and if we don't incorporate those lessons into the work, we will fail.