Gdula's Golf Simulations: BMW Championship

Volatility is the name of the game in golf, and picking winners isn't easy. With fields of 150-plus golfers sometimes being separated by how a putt or two falls each week, predicting golf can be absurdly tough.

We'll never be able to capture everything that goes into a golfer's expectations for a week, but we can try to account for that by simulating out the weekend and seeing what happens.

The Process

Over the hiatus, I made some tweaks to my original golf model, which used a combination of the OWGR's field strength numbers and datagolf's field strength numbers to adjust each golfer's score relative to the field (on the PGA Tour, the European Tour, and the Korn Ferry Tour). The ultimate goal was to place a score from the Waste Management Open, the BMW International Open, and the Knoxville Open on level playing fields. This adjusted strokes metric lets me see how golfers are performing across all tours. From there, a golfer's adjusted stroke data is combined with their round-to-round variance to see how the field is likely to perform when playing out the event thousands of times.

I liked it, and it worked, but it didn't isolate out tee-to-green and putting performance enough, so I made some alterations, this time leveraging strokes gained data and adjusting that for field strength.

After using an average of those two models, I've now swapped to the newer model, which has fared better and is capable of easier course-level adjustments.

Here are the simulation results for the BMW Championship.

Golfer Simulated
Win Odds
Golfer Simulated
Win Odds
Justin Thomas 8.1% +1200 Jon Rahm 6.7% +950
Bryson DeChambeau 6.3% +1100 Xander Schauffele 5.6% +1800
Rory McIlroy 5.5% +1600 Dustin Johnson 4.0% +700
Webb Simpson 3.9% +1800 Patrick Cantlay 3.9% +3300
Collin Morikawa 3.7% +2000 Hideki Matsuyama 3.5% +3400
Daniel Berger 3.4% +2000 Tyrrell Hatton 3.2% +3700
Patrick Reed 2.9% +2900 Harris English 2.3% +3300
Scottie Scheffler 2.3% +3100 Tony Finau 2.3% +2900
Adam Scott 2.2% +3400 Jason Day 2.0% +2900
Billy Horschel 1.9% +5500 Abraham Ancer 1.7% +6500
Viktor Hovland 1.4% +3300 Kevin Kisner 1.3% +4200
Kevin Na 1.2% +12000 Matt Kuchar 1.1% +10000
Sungjae Im 0.9% +5000 Russell Henley 0.9% +7000
Matthew Fitzpatrick 0.9% +5000 Bubba Watson 0.8% +9000
Paul Casey 0.8% +5000 Gary Woodland 0.8% +8000
Joaquin Niemann 0.8% +13000 Tiger Woods 0.7% +3100
Cameron Champ 0.7% +6500 Marc Leishman 0.7% +9000
Matthew Wolff 0.6% +3300 Joel Dahmen 0.6% +15000

The top-nine golfers (priced +2000 or lower on FanDuel Sportsbook) comprise roughly 45% of the win equity in terms of the betting odds, and that's around 47% in my actual simulations. Simply put, the top 10 golfers or so should win this thing around half the time.

At the top of my simulations sits Justin Thomas (+1200) again, primarily because his tee-to-green game is so complete and has been for the duration of the sample I use (back to 2019 but weighted for more current results). Thomas outperformed his +1200 odds barely in my simulations, one of the few favorites to do so. Xander Schauffele (+1800) also did by about 0.4%, same as Thomas.

The biggest discrepancy, by far, is Dustin Johnson (+700). We all saw what DJ did last week, but +700 odds imply he should be around 12.5% likely to win, and that's just not really feasible in a field this top-heavy.

There's value again on Patrick Cantlay (+3300) because of his great long-term stats, yet we'll have to feel okay going back to him after a missed cut last week. Helping me feel okay with that is the fact that Cantlay was (slightly) positive in all three tee-to-green stats (when adjusted for field) but lost a ton of strokes putting.

Hideki Matsuyama (+3400) and Tyrrell Hatton (+3700) -- along with Cantlay -- were my top bets last week, and they're undervalued again. Simply put: their stats outperform their betting odds.

I'm not overly interested in long shots this week because we're getting four full rounds of every golfer, meaning the studs are guaranteed more time to separate. The odds that one of them does is all that matters (like we saw with Dustin Johnson last week). That said, longer golfers who outperformed their posted odds in my simulations include: Kevin Na (+12000), Abraham Ancer (+6500), Matt Kuchar (+10000), and Billy Horschel (+5500).

So far, I've bet Bryson DeChambeau, Rory McIlroy, and Cameron Champ outrights.