We all know this of course,

...but it's always good to be reminded.  Bill James writes:

It's never safe to generalize from a sample of one.

The entire exchange:

Gregg Jefferies did an extraordinary amount of practice as a teenager, and he also peaked at an early age. To what extent are those related, if at all?

Asked by: 110phil

Answered: 10/27/2014

Paul McCartney did an extraordinary amount of singin' and guitar playin' as a teenager--and it still touring today. It's never safe to generalize from a sample of one.