Spieth's course history bump at Colonial

Somewhat surprisingly (to me) we have Spieth as the highest rated golfer this week. This is possible because of his course history bump (+0.29 strokes/round), which is based off his 32 rounds at Colonial performing ~1.1 strokes better than expected. What do you think, is this adjustment for Spieth’s history at Colonial too large?

What if his course history performance is driven by a higher variance skill like putting? We make strokes gained category adjustments to our baselines, why not to course history?

Here’s his historical putting at Colonial fwiw… +0.82 per round. Link.

Spieth is gaining .82 strokes gained at Colonial in putting. However, Spieth has been historically an above average putter. I am guessing he was expected to gain something around half a stroke putting. Therefore, it seems Spieth’s over performance at Colonial can be slightly attributed to putting but also a lot from tee to green.

That being said I think adjustments for course history based on strokes gained categories is definitely something to investigate further. There might be some cases where a player likes a course and plays it well but due to high variance putting they look like they play the course average or poorly.

On the topic of adjusting for course history, have you guys ever looked into how players perform on certain green types? I have heard commentators make statements before such as “this player putts well on bermuda greens”.

I agree. Would want to know Spieth SGP related to his baseline.

He has been playing like a +2.2 SG golfer lately and received a +0.3 SG bump for the week. So why was he given only a 5.9% chance of winning? That’s a price that’s consistent with a +1.4 SG golfer with a +0.3 SG bump (for a total of +1.7), which implies that the model is undervaluing him by 0.8 SG.

Yes, he’s been playing like a +2.2 player lately, but so has Brian Harman! I don’t think Spieth’s baseline should be near +2.2 currently, because, for one, we always expect some regression (so to have a skill near +2.2 you need an historical average of scores near +2.4 or so). Second, there is simply a lot of parity in golf right now. Rahm is our highest ranked player with a baseline skill of ~2. I’m not sure if that’s just because we are in a temporary situation where none of the top guys have strung together great stretches of golf, or if it’s because the true gap between the best and average player is shrinking.

In any case, I don’t Spieth has proven he’s the best player in the game at the moment. Maybe a Top 5 player. It requires more than a few months hovering around +2 SG/round. Also here is the breakdown of Spieth’s skill this week.