I.T.N. No. 24
PUBLISHED February 22, 2021
Inside The Numbers ...
is a brief numerical summary of the current happenings in the world golf, published every Monday — hopefully.
3055 DAYS
One of the most interesting — but least visited — parts of our website is the amateur rankings and the accompanying archives. For example, it's nothing short of fascinating to look at the state of the amateur game 3055 days ago. Shown below are the top 10 amateurs on October 12, 2012: The DG Index here is our estimate of a golfer's skill in strokes-gained per round relative to the average golfer in the NCAA D1 Championship (which we have as about 2.3 strokes worse than the average PGA Tour player). This specific amateur class was one of the best in recent memory; for reference, the current top ranked amateur has a DG Index of just +1.67. Some of the more interesting names from the October 12 rankings don't appear in the Top 10: Jon Rahm is #157, a skinnier version of Bryson DeChambeau is #66, and Xander Schauffele is #237.
This past weekend Max Homa beat the strongest field of the 2021 season. Back in 2017, Homa's average performance for the year was 2.7 strokes worse than an average PGA Tour player — roughly on par with the typical Latinoamerica Tour professional. At this pace Homa should reach peak-Tiger levels by 2025:
It's a narrative that doesn't warrant further repetition, but hear it is anyways: Tony Finau just can't find a way to get it done on Sundays. Finau started the final round of the Genesis Invitational in a tie for fifth, four shots back of leader Sam Burns. From this position, our model gave Finau an outside shot of winning at 4%. Sixty-four strokes later, which was good enough for the best round of the day by 2 shots, our model estimated that Finau's performance would convert to a win 33% of the time (depending on how the other players performed near the top of the leaderboard). That is, Finau's final round performance was worth 0.33 expected wins. This was Finau's second highest win probability on the PGA Tour using the conditional-on-round-four-performance definition. Interestingly, in his lone PGA Tour win at the 2016 Puerto Rico Open, Finau earned just 0.03 expected wins using this metric. That's golf.
The Puerto Rico Open, which sits opposite a World Golf Championship on the PGA Tour schedule, always draws a diverse group of golfers. That is, some of the golfers are pretty good, and some of them are really bad. This diversity manifests itself in an interesting, and perhaps profitable, way: there are 28 golfers with 'made cut' probabilities above 75% in this week's edition of the PR Open. This is by far the highest such figure in any of our tournament predictions for full-field events since the PGA Tour switched to the current cut rule of Top 65 and ties. Part of this can be attributed to the slightly smaller field size this week (132 golfers), however its mostly due to the field's unique skill distribution:
Shown here are the distributions of golfer skill in last week's Genesis Invitational (red) and this week's Puerto Rico Open (blue). What is important here is the shape of the distribution: skill at the Genesis was roughly normally distributed while skill in this week's event shows a long left tail. The result is that there is a fairly large group of golfers (skill between -0.5 to +0.5) who are substantially better than the average player in the Puerto Rico Open field. This uniqueness in field composition is easily accounted for if you are simulating the tournament to estimate finish probabilities, but could be tricky without simulation. As a result, there could be a lot of value betting on the top players to make the cut this week.