Is there any evidence that crunch actually helps? In my experience crunch time increases productivity for a couple of weeks and is a net negative from then on.

Is there any evidence that crunch actually helps? In my experience crunch time increases productivity for a couple of weeks and is a net negative from then on. Tired, stressed, and sick/absent developers just aren't as effective. Producing poorer code, even at a faster rate, is usually a loss as well. Any software development organization that practices it would seem to be sabotaging themselves.