Earlier this month, Ken Pomeroy had a look at which statistics most significantly impact a team’s win probability in a game that is tied at the half. The biggest impact he found in in the three-point shooting category.
Namely: if you shot it worse from outside than your opponent in the first half, that’s worth about a 7% boost to you in win probability in the second half. Why? Basically, regression is going to catch up to both teams over the long run, which is good news for the team that shot it poorly and bad news for the team that shot well:
(I yoinked the above from Ken’s post.