You've been talking to the wrong hardware engineers, I think. Every engineer on my team has a characteristic "fudge factor" that represents his... optimism (sa

You've been talking to the wrong hardware engineers, I think. Every engineer on my team has a characteristic "fudge factor" that represents his... optimism (say, from 1.5x to 2.5x). Once I apply those fudge factors, I add another 30% slack to the total schedule. And I usually still underestimate. The team I'm on now has been doing a very good job compared to previous ones about getting good estimates for project duration, but the ability to underestimate is nonlinear in the project size, and most of our projects recently have been pretty small chips. On our most recent tapeout, we did a new baseline based on a new feature request and underestimated the cost of that feature addition by a factor of 2. The total schedule was pushed out about 20% as a result. I still consider this a success in predicting the project's duration: I've been on projects where we taped out six months or more after our "commit" date.