A chink in the armor of Fargorate

JC

Coos Cues
A 100 point spread between players predicts that the higher player will win two games for every one game the lower player wins.

But all games are not created equal and all 100 point spreads are not linear.

Take a nine ball race to 18. A 600 player is expected to beat a 500 player 12 times. This may well hold true because a 600 player will make mistakes leaving the 500 player some short outs even though the 500 can't run 6 balls. Now take a 700 player and a 600 player. Same result different reasons. The 600 player can actually run out enough to make the equation balance even though the 700 player isn't leaving him any 2 or 3 ball outs or hanging 9s. So life is good right? Not really.

Now the game switches to 8 ball. The 600 player can still run out some against the 700 player so it may finish fairly close to expected depending on the break format. Here comes the rub though. The 500 player could play the 600 player 8 ball all day and all night and be lucky to win a single game. Because all games are not equal even though Fargo treats them as such.

Having reported Fargo for a couple sessions now I see anecdotal evidence that this is true. The top players go down some during 9 ball and back up when 8 ball starts. This is the expected result though IMO because once again, all games are not equal.

JC
 

hang-the-9

AzB Silver Member
Silver Member
Are you talking about the fact that in 9 ball you can lose by leaving the last few balls easy for the weaker player and in 8 ball they would still need to run out their own balls first? So a player that may be able to win by sinking one ball in 9 ball may not win the same game in 8 ball because they still need to run their balls?

That may be an issue but it's pretty specific, I have lost many games of 8 ball to weaker players because even though they would miss, the fact that they have their balls on the table would block my shot on the 8 ball or my last ball or something. They not only would need to miss, but also leave a good shot for you.
 

donuteric

always a newbie
Silver Member
The 500 player could play the 600 player 8 ball all day and all night and be lucky to win a single game.

I'm not entirely sure I understand how a 100pt-lower player is only able to win one 8-ball game in a long session. The differences between 8-ball and rotation games are certainly well appreciated. In my experience, for roughly a hundred point difference, it has been approximately 2 to 1. DW and I are 200 points difference. We play awfully a lot against each other at home, from 8- to 10-ball, and my anecdotal observation has likely been around 4 to 1.
 

BasementDweller

AzB Silver Member
Silver Member
A 100 point spread between players predicts that the higher player will win two games for every one game the lower player wins.

But all games are not created equal and all 100 point spreads are not linear.
(...)

JC

I kind of thought this too BUT I'm fairly certain that Mike has shown that there's very little difference between the results when the games are 8, 9, or 10 ball. I think he has the data to back this up too.
 

JC

Coos Cues
I kind of thought this too BUT I'm fairly certain that Mike has shown that there's very little difference between the results when the games are 8, 9, or 10 ball. I think he has the data to back this up too.

In certain spectrum that's probably true. The discrepancy opens up wider for 8 ball when the weaker player can't run out an open table.

As I said all the stronger players in our little bca league went down some points during summer rotation and all of them are on the increase with the 8 ball season under way. It's not huge due to robustness acting as a shock absorber but it's there and it's not nothing.

JC
 

skip100

AzB Silver Member
Silver Member
FargoRate also ignores the potentially substantial difference in the margins between winner breaks vs alternate break formats.
 

robsnotes4u

AzB Silver Member
Silver Member
I kind of thought this too BUT I'm fairly certain that Mike has shown that there's very little difference between the results when the games are 8, 9, or 10 ball. I think he has the data to back this up too.

You are correct, Mike has shown this many times.
 

Dimeball

AzB Silver Member
Silver Member
FargoRate also ignores the potentially substantial difference in the margins between winner breaks vs alternate break formats.
True, alternate breaks favor the weaker player regardless of the averages. Hell, we all know why alternate break came about, an attempt to handicap the best players. In actuality it gave false hope to the lazy and less talented. SVB still wins most of the tourneys he plays and is year in year out 6 figure winner.

Think about it, would Earl win a few more tournaments if it was still winner break... hmmm?
 

skip100

AzB Silver Member
Silver Member
True, alternate breaks favor the weaker player regardless of the averages. Hell, we all know why alternate break came about, an attempt to handicap the best players. In actuality it gave false hope to the lazy and less talented. SVB still wins most of the tourneys he plays and is year in year out 6 figure winner.

Think about it, would Earl win a few more tournaments if it was still winner break... hmmm?
We've discussed this a bit in the past. It doesn't affect the probability of the better player winning or losing. However it does affect the margin... which is exactly what is used in FargoRate.
 

JC

Coos Cues
You are correct, Mike has shown this many times.

He shows it with mostly data from pro players with very high ratings. The average league players in the 500's and such run different for reasons I've already explained.

JC
 

hang-the-9

AzB Silver Member
Silver Member
He shows it with mostly data from pro players with very high ratings. The average league players in the 500's and such run different for reasons I've already explained.

JC

Average league players are in the 3-400 range. The high rated ones are in the 500 and up. My son and I are both mid 500s, we spot pretty much everyone we play. There is maybe two players out of 6 teams that are ranked higher than us. Fargo is based on overall rating over time, not a single type game or situation. There is also no tracking about 7 vs 9 foot tables which I am sure will be as much of a difference to many players as playing 8 ball or 9 ball, or about how good the tables are. A badly playing table is more of an advantage to a worse player since they often have no idea where the balls will end up anyway.
 

BasementDweller

AzB Silver Member
Silver Member
So the question is: How would a 400 fare against a 500 in 8 ball and 9 ball?

According to FargoRate the 500 should win twice as many at both games over the long run. Or I guess you could have a player that plays at 550 speed in 9 ball and 450 speed in 8 ball so his overall average falls somewhere in between. Could be wrong there since I'm just thinking out loud here.

I guess I'm not seeing the descrepancy. If a 400 level player struggles to run out an open rack while playing 8 ball, wouldn't it be fair to say that this player would also rarely leave open tables for his opponent? Thus making it more difficult for the 500 level player to run out? If they switch to nine ball -- just based on the players I know in these ranges -- it seems like it would still fall into a 2:1 ratio.

Interesting though...I see how there could be 20 or 30 point difference baked into the overall ratings based on game but I'm having a hard time walking through how this would happen on the table.
 
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philly

AzB Silver Member
Silver Member
You do have to tweak. We have a small weekly 9 ball tournament handicapped according to the Fargo system. Normally nothing has to be called. When a good player plays an extremely weak player and the races are 7-2 or 6-2, luck can come into too much play in favor of the weaker player so we came up with a call the 9 scenario. However, if you call the 9 and it does not go but another ball is potted, the player at the table has their inning ended. It has worked so far.

All in all, to my sensibilities, Fargo makes sense. When I look at "my favorites" on the Fargrate site, the ratings make a lot of sense to me as far as where I would personally rate the players on my list.
 

cleary

Honestly, I'm a liar.
Silver Member
So the question is: How would a 400 fare against a 500 in 8 ball and 9 ball?

Another one of Fargo's major flaws. The skill gap between a 450 and a 550 is rather large. The skill gap between a 550 and a 650 can be massive but the skill difference between a 650 and 750 is pretty small. Mostly mental and the 750 has a higher gear but the 650 can run a set out on a bar table. It's not linear. And the table size means A LOT. But whatever... I'm sure I'm wrong.
 

mikepage

AzB Silver Member
Silver Member
A 100 point spread between players predicts that the higher player will win two games for every one game the lower player wins.

But all games are not created equal and all 100 point spreads are not linear.

[...]

This is an interesting issue, and in principle this concern is legitimate. That is, there is nothing inherent that requires the ratings work the same way for different games.

In fact it is not hard to invent a game for which they clearly do not. Here is an example. I'm going to invent a game called SIETE. A single game of SIETE consists of a race to 7 9-ball. The first one to 7 in 9-Ball wins a single game of SIETE. The 100-point-lower player using current Fargo Ratings will not win a third of the games of SIETE as expected but rather will hardly ever win a game. So mixing 9-Ball data and SIETE data would be apples and antelopes.
So what then is the justification for mixing 8-Ball and 9-Ball?

Fargo Ratings started out described as a 9-Ball rating system (2002 Billiards Digest article). Then by 2010 a simplified version of it was being used as an 8-Ball rating system, with 13,000 games amongst 320 players. Over the next several years we started collecting some 9-Ball data but didn't consider combining the data for two reasons: (1) we bought into the conventional wisdom that people's 8-Ball and 9-Ball speeds were two completely different things, and (2) the kinds of things that John mentions here.

By the fall of 2014, we had 20 times as much data and 20 times as many players, and we were doing separate ratings for 9-ball (and 10-Ball) and for 8-Ball. And in fact we were doing separate ratings for different table sizes. We started noticing that the players largely had the same ordering and largely had the same rating gaps. So we started investigating. Did 8-ball and 9-Ball work the same? Did 7-foot and 9-foot ratios work the same? We had enough data to determine that remarkably so they did.

There is a huge incentive to combine data if it is at all reasonable to do so because many of your opponents who would be unestablished on, say, 9-Ball on 7-foot tables, are established when we consider other games. Think about this. Suppose you are offered a 7-foot 9-Ball big gambling match against some unknown opponent named Vilmos, and you ask a friend how Vilmos plays. Your friend says he has never seen Vilmos play on a 7-foot table, but on a 9-foot table he plays even with Oscar Dominguez. Are you going to think this is irrelevant knowledge? Of course not. Combining games and table sizes allows the FargoRate optimization to take advantage of similar situations, and these situations are the rule rather than the exception.

JC mentioned that I often use data from pro players in my analytical examples. There are two reasons for this. First we have a lot of data on top players. And second, people are familiar with the names and have seen them play.

What I've done here is to look at my own data. I am rated 623. So I think to investigate John's point, I should compare myself to someone rated 523 in both 8-Ball and 9-Ball. It is hard to get enough numbers to be statistically meaningful. But here is what I did. I looked at my own record against opponents within 20 points of 523 (from 503 to 543) in both 8-Ball and 9-Ball. This should average about a 100 point gap. At 100 points, I am expected to win 67% (two thirds) of the games.

I played 366 games of 9-Ball against opponents 503 to 543 and 981 games of 8-Ball.

I won 66.9% of the 9-Ball games
I won 68.0% of the 8-Ball games

It works out about as expected.

Now, with 6.4 million games in the system, we are up another factor of 20 from the Fall of 2014. We have plenty of data to analyze all sorts of things. We are not wedded to any particular thing we are doing. If the data suggests there is a better way, there is no reason we wouldn't just switch to that way.

Taking deep dives into our data is part of the fun for numerophiles like me ;-)
 

jasonlaus

Rep for Smorg
Silver Member
Since Mike seems to be the only one who can access the data, he's able to cherry pick situations that work in his favor...

Well, at least you're consistent on bashing him.

I'd put you at an 815 Fargo for bashing
Jason
 

alphadog

AzB Silver Member
Silver Member
Well, at least you're consistent on bashing him.

I'd put you at an 815 Fargo for bashing
Jason

Damn Jason just when I thought... you come up with this. Priceless. I think 815 is probanly about right.
I will say this,about cleary,he does seem to a sceptic about many things,fargorate doesnt garner all his cynicism.
 

mikepage

AzB Silver Member
Silver Member
Another one of Fargo's major flaws. The skill gap between a 450 and a 550 is rather large. The skill gap between a 550 and a 650 can be massive but the skill difference between a 650 and 750 is pretty small. Mostly mental and the 750 has a higher gear but the 650 can run a set out on a bar table. It's not linear. And the table size means A LOT. But whatever... I'm sure I'm wrong.



I would say your claim doesn't rise to the level of being wrong.
Without defining "skill gap" it has no meaning and cannot be right or wrong.

Most 200s can become 300s by playing an hour a day for a few months
Most 300s can become 400s by playing an hour a day for a year.
Few 600s will become 700s even by playing an hour a day for a lifetime
No 700s will become 800s by playing an hour a day for a lifetime

Clearly these rating gaps, numerically the same, mean vastly different things when it comes to acquiring skills.

The RATING GAPS are well defined. In each case the higher rating wins 2 to 1 over the lower player. Skill gap is a vague concept. You could equate it to a rating gap if you want. Or you could define it in a a number of different ways. Or you could not define it and be #notevenwrong
 
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