This is a good point. I've had much better luck estimating using the outside view, as Kahneman calls it (or willful ignorance, as Weisberg calls it). I think t

This is a good point. I've had much better luck estimating using the outside view, as Kahneman calls it (or willful ignorance, as Weisberg calls it). I think the problem is people in IT (including developers) don't have much statistical training. Taking the outside view and believing it requires faith in statistical principles. The people I meet in our field want to hear about nice narratives and specific examples, not reference-class generalisations and probability distributions.