How much does a prospect's birthdate matter?

Among many things Jack Eichel and Auston Matthews have in common, they both have birthdays after Sept. 15, which pushed them back a draft class. Getty Images

In some of the biggest debates about top NHL draft prospects in recent years, one trend has been common among them. It existed in Connor McDavid vs. Jack Eichel, Taylor Hall vs. Tyler Seguin, Nathan MacKinnon vs. Seth Jones, Aaron Ekblad vs. Sam Reinhart and this draft season with Auston Matthews vs. Patrik Laine. One of these prospects played a full extra season of hockey prior to being drafted due to having a late birthdate, and the other didn’t.

Since I started doing work in the hockey prospect arena, the issue of late-birthdate prospects confounded me. After years of dealing with prospects, and doing recent research on the matter, I am convinced it is one of the most important quantitative factors that can go into prospect evaluations.