[AlbertCory]

Thank you, quietbritishjim. I actually met Dr. Kahneman at Google, although I didn't introduce him. I got to ask him at lunch:

"Dr. Kahneman, you've been at this for 40 years. Do you think you've changed anyone's ways of thinking?"

He smiled and said "No, not even my own!" and then recounted how in his personal life he'd made a mistake which he'd written about extensively (not the one about planning, though). It's a human failing, not a methodological one.

I'm also vague about his example, but I think it was a new textbook. He asked his committee to reflect on their own past experiences with similar books. "Two years" was the past experience. Then they decided that it really should be six months, and that's the estimate they went with.

No one wants to accept that shit happens and it's going to happen again. That's why estimation is hard.