August Madness? A statistical look at the U.S. Amateur bracket
- USGA/Chris Keane photo
- USGA/Chris Keane photo

By David Tenneson

The 120th iteration of the U.S. Amateur is being played at the Bandon Dunes Resort on the Oregon coast. First played in 1895, the USGA’s oldest championship has gone through a number of format changes. Since 1979, this week-long event has featured a mix of stroke play and match play in order to crown a champion from a field of over 300 of the world’s best male amateur players.

The first stage of the event consists of two stroke play rounds, and there is typically a sudden-death playoff conducted on the morning of the third day to narrow the field into a match play bracket of exactly 64 players.

There’s something uniquely thrilling about the idea of a bracketed tournament, for spectators as much as the competitors themselves. Survive and advance, as the saying goes.

One of the most scrutinized bracketed tournaments in sports is the NCAA Men’s basketball tournament held annually in March. Over the years, statisticians have collected and analyzed historical results in different ways, looking for trends that not only explain what transpired but might also help predict future outcomes. There are a few parallels between the basketball tournament and US Amateur match play brackets. The obvious is the 64 seeds (excluding basketball’s play-in games), but there’s also the “specialness” quality that make both extremely exciting to follow as a spectator. Even so, there are very few diehard golf fans pouring over bracket scenarios the way basketball fans do in March.

Still, it is possible to apply some of the same statistical analysis methods used on college basketball data to draw some potentially relevant trends from past U.S. Amateur results.

Analyzing historical U.S. Amateur match play brackets

Focusing on match play data from 2000-2019, we can collect some interesting data points. One place to start is by analyzing the first round (Round of 64) which has fixed match-ups. Looking at this table sorted by success rate for the top 32 of 64 seeds, we see that while being highly seeded is important, there are still some single-digit seeds (9 and 4) which have successfully made it out of the first round less than half of the time. Furthermore, even the lowest seeds have been successful more than a quarter of the time they tee it up against players who were either stroke play medalist or within a few shots of the medalist. Part of this might be explained by the sheer randomness of golf, where a bounce off a tree limb or rock can make or break a hole. There’s also the notion of players reacting to their or their opponent’s scores in the golf-equivalent of “clutchness,” which baseball statisticians have been trying to quantify in their sport for years. An additional factor that makes match play unique is the fact that no matter how out of hand a hole gets, the player can lose no more than one hole at a time (as opposed to many strokes at a time in stroke play), which in some cases skews the normal risk/reward factor.

You might be thinking the data looks different when organized as seeds 1-64 instead of the beloved basketball-style bracket regions (with four regions of 1-16 seeds). With that in mind, what follows is the same dataset with the U.S. Am seeds adjusted to the 1-16 numbering basketball fans are used to seeing.

As seen with the “true” 64-slot seeding, the basketball style re-seeding shows how the #1 seed is successful in the first round approximately two-thirds of the time. Also, the higher seeds have been more successful than the lower seeds, but at a rate that is essentially a coin-flip. Note that the #2 seed has actually had a higher success rate than the #1 seed. When filling out NCAA tournament brackets, many fans focus on the matchups that have more balanced (50%) success rates as areas for potential upsets, such as the infamous #5 vs #12 matchup. Using this US Amateur data table, most of the matchups are close to balanced, giving statistical backing to the survive-and-advance mindset that is amplified in golf match play where advancing to the next round is not a given for any seed.

After examining the first round U.S. Amateur results, we can then expand this notion all the way to the Finals match. The tables below show the probability of advancing to each round for all 64 seeds. One area to focus on is the rounds in which each seed has struggled. For example, the #5 seed, which is one of the most successful in the first round, has struggled to pass beyond the Round of 32.

It is interesting to note that in the last 20 U.S. Amateurs, only three times has any of the top 18 match play seeds gone on to win. But look at seeds 19-38, where 12 of the 20 past champions were seeded, comfortably in the middle of the bracket.

The #1 seed doesn't seem to provide any assurances after the first round (or maybe two) of match play, although the "medalist jinx" (losing in the first match) doesn't seem to be a thing either. The one #1 seed to win in the last 20 years was Ryan Moore, who also won the NCAA Championship, U.S. Public Links, Western, and Sahalee Players championships that year (2004). Perhaps the most surprising thing of all is the fact that the bottom seeds have yielded two champions. In fact, the bottom four seeds have been more successful in the Finals match than the top four seeds, going 2/2 compared the 1/3 success rate of the top seeds. That is some excitement that college basketball fans are statistically likely to never see.

So what does it all mean? Potentially nothing! We just don’t have enough data here to draw any meaningful conclusions. Even with all match play results dating back to the format change in 1979 (or even further), the whole “past performance is no guarantee of future results” adage is still a thing. We can see that there are some statistically-relevant takeaways from looking at the historical records, but no golfer is sitting over a 15 foot birdie putt to extend the match thinking “well I was 17% more likely to win this match based on my seeding, so this putt is 17% more likely to go in.”

In reality, players that make the stroke play cut aren’t usually worried about their seeding and potential match play path. In the end, all that matters is surviving and advancing until the Havemeyer Trophy is in hand.

ABOUT THE U.S. Amateur

The U.S. Amateur, the oldest USGA championship, was first played in 1895 at Newport Golf Club in Rhode Island. The event, which has no age restriction, is open to those with a Handicap Index of 2.4 or lower. It is one of 14 national championships conducted annually by the USGA, 10 of which are strictly for amateurs. It is the pre-eminent amateur competition in the world. Applications are typically placed online in the spring at www.usga.org.

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