I.T.N. No. 22
PUBLISHED August 25, 2020
Inside The Numbers ...
is a brief numerical summary of the current happenings in the world golf, published every Monday — hopefully.
Due to (un)popular demand, we are once again providing live-updating probabilities and projections for various outcomes related to the FedExCup Playoffs. One such outcome of interest is the number of positions in the TOUR Championship field that are not yet determined. It turns out only 7 of the 30 spots at East Lake are realistically up for grabs; in our 50,000 simulations, the golfers currently ranked 1-20 advanced in every single simulation, while the 3 golfers in positions 21-23 all had advance probabilities above 99.95%.

It might be worth bookmarking this post in case a player currently ranked better than 24th fails to advance to East Lake!
Continuing with our FedExCup predictions, it is also interesting to speculate on the point total that will be required to advance to the Tour Championship. Of course, this point cutoff is itself a random quantity; plotted below is the point tally of the last player (i.e. 30th in the FedEx rankings at week's end) to advance to East Lake in each of our 50K simulations:
The dashed red line indicates the median of the distribution and is equal to 977 points. By looking at the FedexCup point allocation for this week we can get a rough sense of the kind of performance required of each player to advance. For example, Tiger Woods currently sits at 57th in the FedExCup standings with 620 points; therefore, to reach the lowest simulated cutoff of 902 points, Tiger would need to finish in a 2-way tie for 6th (points are averaged across the finish positions involved in the tie).

It's also worth pointing out that some of the simulations had point cutoffs higher than the current point total of the 17th ranked player in the FedExCup — who, in the note previous to this one, we claimed was guaranteed to advance! Is this a contradiction? No, it just means a scenario wherein the 30th ranked player has more than 1125 points at week's end requires that the current 17th ranked player earns more than that.
With all that has been written and said about Dustin Johnson's 11-stroke victory at last week's THE NORTHERN TRUST, what may perhaps go unrecognized is that this ridiculous win margin was achieved against one of the strongest fields in golf. This of course begs the question: where does DJ's performance rank historically among the all-time great performances in professional golf? First, for reference, last week Johnson gained 5.9 strokes per round over the field; we deemed this to be worth 6.5 true strokes-gained per round, as the average player in THE NORTHERN TRUST field was about 0.6 shots better than an average PGA Tour field.

Now, to the good stuff: according to our true strokes-gained metric, which estimates each golfer's performance relative to the average PGA Tour field in that season, there have been just 9 weeklong performances since 1983 better than Johnson's 11-shot romp last week. Predictably, the best strokes-gained performance of all-time belongs to Tiger at the 2000 U.S. Open, where we estimated he gained 7.8 strokes per round over an average PGA Tour player. Henrik Stenson and Phil Mickelson's performances in their duel at the 2016 British Open also came in ahead of DJ, although those were heavily aided by a big wave split. Other notables in the top 9 performances include Tiger's 1997 Masters win, Greg Norman's 1994 win at The Players, and Phil's 2006 win at the BellSouth Classic. Pretty elite company for Deej.
As those who follow golf closely know, Will Zalatoris is having a special season on the Korn Ferry Tour. In an old blog, we documented how rare it is for a golfer on a development tour to perform at the level of an average PGA Tour professional for the duration of a season; it happened just 22 times on the Korn Ferry circuit from 2015-2017. So far in the 2020 season, Zalatoris has averaged +1.27 true strokes-gained per round. This is the 22nd best such average among golfers on any tour in 2020, and it is 0.86 strokes per round better than the second-best average among Korn Ferry Tour players. When you put it all together, our model ranks Zalatoris as the 38th best player in the world — just ahead of another promising young player, Matthew Wolff.
How messed up have things become since the coronavirus took hold? It's possible that the best-performing golfer in the world will not be in the 2020 Masters, despite being healthy and willing to play. Barring a last-minute invitation, Daniel Berger will not be this fall's Masters field; Berger is currently 6th in our rankings and first in our trending table, averaging a ridiculous +2.77 true strokes-gained per round over his last 20 rounds. It's important to notice that I used the phrase best-performing above; the DG Rankings only use total strokes-gained (adjusted for field strength) to determine a golfer's position, as total strokes-gained is the measure of performance that ultimately matters in golf. However, once we make adjustments for the differential predictive power of the strokes-gained categories, Berger falls to the 13th-rated golfer by our model. That is, even though the quality of Berger's recent performances is surpassed by only 5 golfers, when it comes to predicting future performance, there are 12 golfers we expect to be better. This is largely driven by the the fact that, inevitably, a portion of Berger's excellent recent performances have been driven by putting — and we know short-term fluctuations in putting are not very predictive of future putting performance.