A new measure of tournament toughness: Harmonic Field Strength

The first is (850/1+780/2)/(1/1+1/2) = 826.66

The second is (830/1+820/2)/(1/1+1/2) = 826.66
I would be definitely more interested in the second event (830 vs 820) over a 850 vs 780 although the HFS is the same for both events. Maybe going to 16 or 32 will present a truer picture of the strengths of the events.
Funny that the numbers came out the same in my example though lol
Bob had a typo. The one you prefer is 840 and the other is 826.
Okay, now I feel better 😌
 
I recall we used to utilize a system locally, that there was a "strength coeffitient" for every tournament run under this system. Based on rankings of every player involved. And finishing high at a "stronger" (harder) tournament added to player's ranking more than similar finish at a lesser tournament.
 
We are working on Monte Carlo simulations to find an optimum exponent. I have a sneaking suspicion it may actually need to go in the other direction! We’ll see.
A simpler way to discount the top players a little is to start with 1/2 rather than 1/1 for the weight.

What is the "goodness" criterion in the simulations of different weight exponents?
 
A simpler way to discount the top players a little is to start with 1/2 rather than 1/1 for the weight.

What is the "goodness" criterion in the simulations of different weight exponents?
I think the best way is expected $$ or expected points with typical distributions, not something like chance of winning.
 
How Strong Was the Field?
Harmonic Field Strength (HFS)
as a New Way to Measure Tournament Toughness



Pool pundits battle about whether the European Open or the World 10-Ball Championship had the stronger field—or which event truly ran deepest in 2025. Or which tournaments should be considered majors.

These debates almost always come down to some version of the same tradeoff:
star power vs. depth — comparing the top few entrants to the overall quality and density of the field.

Panozzo might argue the star-power side this time, pointing out that Filler, Gorst, SVB, and FSR were all in the field of some tournament. Or he might count how many of the World Nineball Tour top 10 were there. Or how many players were rated over 830.

The other Mike might counter that while Panozzo’s event had a few more marquee names, this other field, with more players traveling from Asia, ran deeper and included more of the top 100 or more players over 800 or 780.

Both sides have a point. It’s a good instinct to care about both star power and depth. How hard it is to win — or just to go deep — really does depend on both. It is more likely for a top contender to get snake-bit early when the field runs deep.

Until now, though, we haven’t had a unified way to balance that tension in a single number.

Introducing: Harmonic Field Strength (HFS)

You’ve probably come across some version of the 80/20 rule, also known as the Pareto Principle -- 20% of the people do 80% of the work. Or 20% of the seals do 80% of the barking.

That idea reflects a deeper pattern called a power law, where impact isn’t spread evenly but instead tapers off from the biggest contributors to the many smaller ones.

The same pattern appears in tournament field strength.

  • We care a lot about the presence or absence of the top five or ten players.
  • We care somewhat about the next 30 or 40.
  • And we care very little about whether the bottom half of a 256-player field is rated 680 or 610 — or even whether they’re there at all.
To account for that uneven importance we borrow a concept from economics and physics: A harmonic-style average that naturally emphasizes the top-ranked players while still incorporating the strength of the rest in a balanced way.

What is HFS?

Harmonic Field Strength (HFS)
is a single-number summary, a rating-style average that weights each player’s contribution by the reciprocal of their rank, where rank here comes from a top-to-bottom ordering of the players in the field by Fargo Rating.

  • The 2nd-highest rating counts half as much as the top rating.
  • The 3rd counts one-third
  • The tenth counts one-tenth.
  • And so on — through the top 64 players.
This produces a number that:

  • ✔️ Looks like a player rating
  • ⚖️ Reflects both star power and depth
  • 📊 Allows clean comparison between tournaments
📊 An Illustration: Bali vs Hanoi

Two overlapping events happened in 2025:

  • 🌴 World 8-Ball Championship in Bali (Filler, SVB, …)
  • 🏙️ Hanoi Open (Gorst, FSR, …)
Which field was tougher?

By average rating of the top 16
, Bali is a smidge ahead, by less than a point. But when we reach further to consider the top 32 or top 64, the tide changes and Hanoi looks stronger. The average rating of the top 64 players is 801.3 for Hanoi and 792.2 for Bali. HFS conbines the influence of the top 64 players and reveals Hanoi as the stronger field overall.

Event HFS Score
Hanoi Open 825.2
World 8-Ball 824.6

What About Other Events?

Here’s a taste of what HFS reveals:

  • Eurotour events, Derby City 9-Ball and Super Billiards Expo come out comparably tough.
  • The Battle of the Bull (Roanoke VA) ranks right alongside Bali and Hanoi, surprising perhaps, until you note its proximity to the US Open
View attachment 857670

🏆 Which tournament had the toughest field in 2025?

What about these big ones?

  • China Open
  • Las Vegas Open
  • US Open 9-Ball
  • World 10-Ball
  • UK Open
  • Florida Open
  • World Pool Championship
  • Peri Open
  • International Open
Which one do you think had the strongest field?
What are the top three picks?

We’ll compile the full numbers and share the results soon.
Good stuff. Long overdue and high time there is proper method to rate rank tournaments objectively.
I would take your conclusions over the other Mike. No offence to other Mike but he bases his conclusions mostly eyeball, anecdotal on smaller subset of data rather than statistical :LOL:

Sounds about right that Hanoi Open and W8B about same strength as they both have at least 2 dozen 800s players.
Are Peri Open and WPC the strongest tournaments of the year? cos I see both those events have 40+ 800s players
 
Good stuff. Long overdue and high time there is proper method to rate rank tournaments objectively.
I would take your conclusions over the other Mike. No offence to other Mike but he bases his conclusions mostly eyeball, anecdotal on smaller subset of data rather than statistical :LOL:

Sounds about right that Hanoi Open and W8B about same strength as they both have at least 2 dozen 800s players.
Are Peri Open and WPC the strongest tournaments of the year? cos I see both those events have 40+ 800s players
"Eyeballing" I would say 1.W9, 2. US Open, and 3. Peri/W10b.
Curious how the results turn out.
 
[...]

More importantly, completely throwing away the bottom players, 65+, seems rather extreme. Just for example, in the Hanoi there were a number of upsets of tip-top players: Gorst, Raga, Roda, and FSR. The more rounds there are, the more players like Antonakis, Kiet, and Sevastyanov the top 64 have to fight through. So more players--and therefore more rounds--makes the tournament tougher, even before considering that more rounds just makes the marathon that much longer. Tyler Styer lost round one to an unknown in Hanoi--how much does having 256 entrants vs 96 matter when you have to fight more rounds to get to the money?

Again, I think it's a very interesting idea, but the method presented sounds predicated on faulty/poor assumptions.
Having an extra round or a few extra rounds where you might get clipped by a weaker player matters less than it seems at first glance.

Let's say 64 800-level players are going to play a single elimination tournament on Saturday.

Then on Sunday those same 64 players play in a 128-player SE tournament with an extra round in which they each face a 700-level opponent who will upset them 10% of the time.

If you don't think it through, you might conclude that since you only have a 90% chance of even GETTING to the round of 64 that you now have a 90% of Saturday's chance of winning--i.e., that the tournament got tougher for you by the chance you get eliminated in the extra round.

But that's not true. Most of that 10% ding you get back through the fact that around 5-6 OTHER 800-level players have also been eliminated and so you now have a 10% chance of getting an easy round-of-64 draw if you DO get there.

Bottom line the effect of that extra round is small for you --and smaller than most people think.

In the 64 player tournament, you have a 50% chance of reaching the round of 32
In the 128-player tournament you have a 48.6% chance of reaching the round of 32 (not the 45% you'd conclude if you're just thinking about the 1st-round exit)
 
Given the battle of the bull has highest HFS, I think it isn't a particularly useful measurement point.

There are 7 tournament fields rated higher than Battle of the Bull that are not on this chart. Perhaps you understood that, and still felt this just doesn't pass the smell test. Here is the top part of Battle of the Bull field shown along side of Hanoi Open. Players opposite one another are either the same player or roughly equivalent.

Looking at just this part of the field, Hanoi has Jayson Shaw with no partner counter-player, and Battle of the Bull has SVB, Oi, and Kazakis with no counter-players. That's enough to give Battle of the Bull an early lead.
Beyond this Hanoi is deeper (50 players over 780 vs 45).
Player 64 for Hanoi is 772 vs 751
That depth is enough to balance the early lead such that the fields are judged of similar strength.

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Back in 1983, the computer world had been using Harmonic mean to rank different computer systems and assign a single number which could be compared. This had been in use for nearly 2 decades--mid-late 1960s ...

Then some mathematical people go together and showed that using the Geometric mean was a better representation of system-to-system performance comparisons. {See Story of SPECmark} We have been using GeoMean since then. And for those that can read "math" papers::


For this particular comparison, pick the top 50-to-500 players into an eXcel data sheet and what rating system you use {Fargo, ...} value and simply GeoMean( field ) for a final result to be compared.
 
I think I like the metric; at least the label. You might also include Fargo/field density if that's not built in. This would distinguish between identical Fargos. IOW if you took 1K Fargo 750s and made 'em go to the death, you'd end up with the best 750s and a means to distinguish 749s and less.
 
Having an extra round or a few extra rounds where you might get clipped by a weaker player matters less than it seems at first glance.

Let's say 64 800-level players are going to play a single elimination tournament on Saturday.

Then on Sunday those same 64 players play in a 128-player SE tournament with an extra round in which they each face a 700-level opponent who will upset them 10% of the time.

If you don't think it through, you might conclude that since you only have a 90% chance of even GETTING to the round of 64 that you now have a 90% of Saturday's chance of winning--i.e., that the tournament got tougher for you by the chance you get eliminated in the extra round.

But that's not true. Most of that 10% ding you get back through the fact that around 5-6 OTHER 800-level players have also been eliminated and so you now have a 10% chance of getting an easy round-of-64 draw if you DO get there.

Bottom line the effect of that extra round is small for you --and smaller than most people think.

In the 64 player tournament, you have a 50% chance of reaching the round of 32
In the 128-player tournament you have a 48.6% chance of reaching the round of 32 (not the 45% you'd conclude if you're just thinking about the 1st-round exit)
A few things:

1) 48.6% is still less than 50%
2) no tournament is a bunch of exactly-800 players and a bunch of exactly-700 players. In fields like we are discussing there are multiples in each set of 10. #65 is likely 1-2 points behind number 64. In fact, in a big field, I wouldn't be surprised if number 100 is not too far behind #64.
3) If you have an extra round in a tournament then you have an extra round you have to win. You are looking at it from the perspective of the tip-top players (who, as we saw, can still lose to relative no-names). But for most any individual, including the tip-top players even if the effect is smaller, an extra round or two and twice as many people makes their chances of winning or cashing smaller.

I'm a league player. I play in tournaments with a bunch of 500-600 level players. If I go to Vegas for league nationals and there are many hundreds of players near my skill level, where the last player is not even 50 pts behind the first player, will this gauge of tournament toughness be in any way accurate or useful? It really seems like this is an approximate gauge of tournament toughness for the tip-top pro players, since its shortcomings, while present, don't affect them as much.
 
A few things:
[...]
3) If you have an extra round in a tournament then you have an extra round you have to win. [...]
I'm inviting you to consider that's only part of the effect of the extra round that if considered in isolation leads you to conclude the extra round is more impactful than it really is.

Just for example, in the Hanoi there were a number of upsets of tip-top players: Gorst, Raga, Roda, and FSR. The more rounds there are, the more players like Antonakis, Kiet, and Sevastyanov the top 64 have to fight through. So more players--and therefore more rounds--makes the tournament tougher,

This is true. But it is also true that when
Gorst lost to a 751,
Raga and Roda lost to a 759, and
FSR lost to a 761,
those mid-700s players all got eliminated their next round. That means there were other players--the ones who faced those mid-700s in the subsequent round--who advanced in part because they DIDN'T need to face Gorst, Raga or Roda, or FSR.

A more wholistic treatment of the effect of the extra round includes both of these effects.
 
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