I applaud the willingness to be open about how bad one's estimates are. However, I don't think the full significance of the low correlation coefficient is appreciated here. It's not just that the estimates need to be multiplied by 3 (or 4 or any other number). The correlation coefficient would not go up if one did that.
The real lesson is that knowing the estimate, doesn't really tell you much about how long it will take, regardless of how you modify it. This is important to realize.
> Managers are so deeply prejudiced against the idea that their job requires predicting something which is intrinsically unpredictable, that they will refuse to believe this regardless of how much evidence is presented
Good quote. The tool I linked to is in part built to provide evidence of the difficulty of prediction.
> The real lesson is that knowing the estimate, doesn't really tell you much about how long it will take
Yes and no. My guess is that most teams can improve their accuracy to some degree if they track their accuracy over time. I agree in your greater point of inherent unpredictability though.
The real lesson is that knowing the estimate, doesn't really tell you much about how long it will take, regardless of how you modify it. This is important to realize.
I talk about this more here, in the first section: https://www.rosshartshorn.net/stuffrossthinksabout/managing_...
But long story short, the real lesson is not to spend too much time on predicting, but rather on prioritizing.