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-   -   100%winning Record got bumped down?!?! (http://tt.tennis-warehouse.com/showthread.php?t=451860)

robert 01-21-2013 04:05 PM

100%winning Record got bumped down?!?!
 
Just heard it from someone that he got bumped down to 4.0 with 4-0 in 4.5 last year.

http://tennislink.usta.com/Leagues/M...n/Default.aspx

kylebarendrick 01-21-2013 05:15 PM

Scores were all close, maybe their partner was excellent and the opponents were awful. I have no other ideas...

Ronaldo 01-21-2013 05:16 PM

Shake his hand and congratulate him on getting a pass.

gmatheis 01-21-2013 05:20 PM

He is listed as a 4.0 on every team he has been on recently , so it looks like he was never a 4.5 and therefore did not get bumped down, but rather just didnt get bumped up.

gameboy 01-21-2013 05:55 PM

Wow. whatever they did to update the USTA league site just BLOWS!!! You can't even navigate back and forth went clicking on links. WTF???

Ronaldo 01-21-2013 06:07 PM

Quote:

Originally Posted by gameboy (Post 7145872)
Wow. whatever they did to update the USTA league site just BLOWS!!! You can't even navigate back and forth went clicking on links. WTF???

The site worked? WTF!

schmke 01-21-2013 06:32 PM

Quote:

Originally Posted by gmatheis (Post 7145799)
He is listed as a 4.0 on every team he has been on recently , so it looks like he was never a 4.5 and therefore did not get bumped down, but rather just didnt get bumped up.

Correct. He played on 4.0 teams in 2008 and 2009, then played on a 4.5 team in 2012 but was still a 4.0 and simply didn't get bumped up.

As to why he didn't get bumped up, I estimated him to be a 3.68 starting the year (based on his 2009 season, I think it still carried over to 2012) and moving from 3.68 to over 4.0 in just 4 matches, while possible, is pretty difficult. Couple that with playing 3 of the 4 matches with a self-rated player and a couple of those likely don't generate match ratings for him (only the self-rated player gets match ratings until he has played a few matches) so it may have really just been a couple matches that counted which would be really difficult to improve that much.

In the end, I estimate his dynamic rating at the end of 2012 was 3.90, so he improved but not enough to get bumped up.

Now, his partner in the 3 matches was rated a 4.5C at the end of the year and my estimate agrees with that, having him at 4.43.

Now, the actual skill gap between him and his partner may not be that large, but because he had a starting rating in the lower half for a 4.0, he "helped" his partner get a pretty high initial rating which in turn contributed to his rating only improving to 3.9 despite winning at 4.5.

This is one of the flaws in the system, that playing a lot of matches with the same partner keeps the rating difference between the partners more or less the same. This results in the higher rated partner getting "pushed" up when the team wins.

LuckyR 01-22-2013 07:17 AM

Quote:

Originally Posted by schmke (Post 7145979)
Correct. He played on 4.0 teams in 2008 and 2009, then played on a 4.5 team in 2012 but was still a 4.0 and simply didn't get bumped up.

As to why he didn't get bumped up, I estimated him to be a 3.68 starting the year (based on his 2009 season, I think it still carried over to 2012) and moving from 3.68 to over 4.0 in just 4 matches, while possible, is pretty difficult. Couple that with playing 3 of the 4 matches with a self-rated player and a couple of those likely don't generate match ratings for him (only the self-rated player gets match ratings until he has played a few matches) so it may have really just been a couple matches that counted which would be really difficult to improve that much.

In the end, I estimate his dynamic rating at the end of 2012 was 3.90, so he improved but not enough to get bumped up.

Now, his partner in the 3 matches was rated a 4.5C at the end of the year and my estimate agrees with that, having him at 4.43.

Now, the actual skill gap between him and his partner may not be that large, but because he had a starting rating in the lower half for a 4.0, he "helped" his partner get a pretty high initial rating which in turn contributed to his rating only improving to 3.9 despite winning at 4.5.

This is one of the flaws in the system, that playing a lot of matches with the same partner keeps the rating difference between the partners more or less the same. This results in the higher rated partner getting "pushed" up when the team wins.


I agree that this is the likely explanation for what happened, and I agree with the use of the word: "flaw". Sometimes more complication, calculations and rules lead to illogical conclusions like this case.

gameboy 01-22-2013 07:34 AM

What is so illogical? I think what shmke described is perfectly logical.

So, if you happen to win several matches against self-rated players, you should get bumped no matter what? THAT would be illogical.

schmke 01-22-2013 07:45 AM

Quote:

Originally Posted by LuckyR (Post 7148044)
I agree that this is the likely explanation for what happened, and I agree with the use of the word: "flaw". Sometimes more complication, calculations and rules lead to illogical conclusions like this case.

Perhaps my use of the word flaw was a little strong. It is just how the system behaves when two players partner at doubles all the time. The gap between their ratings will be maintained.

Without some other matches played with other partners and/or singles matches to otherwise adjust one of the individuals ratings, what alternative do you suggest for this situation where matches are always played with the same partner?

You can't just arbitrarily shrink the gap between their ratings as that too many not be correct and may not give the credit due to the higher rated partner. We've just looked at one situation where the big gap seems like an error but I'm sure there are others where a small gap would similarly be an error.

It is just the nature of a system that calculates ratings based on limited data. It isn't perfect, but it is better than many alternatives.

Nellie 01-22-2013 08:04 AM

Also, many of the matches against 4.0 competition had tight scores, so those wins might actually bring down the rating (i.e., if you play 4.0s to a virtual tie, you get a 4.0 rating, even if you are playing in a supposed 4.5 match).

ronray43 01-22-2013 08:57 AM

Still, of the eight opponents he played, all in doubles matches, six of them are rated 4.5 and two rated 4.0. He has proven he's not only competitive as a 4.5, but can win at 4.5. Yet another example of why USTA needs to integrate win-loss record into at least a portion of the NTRP algorithm.

gmatheis 01-22-2013 09:28 AM

Quote:

Originally Posted by ronray43 (Post 7148309)
Still, of the eight opponents he played, all in doubles matches, six of them are rated 4.5 and two rated 4.0. He has proven he's not only competitive as a 4.5, but can win at 4.5. Yet another example of why USTA needs to integrate win-loss record into at least a portion of the NTRP algorithm.

4 matches is hardly enough of a sample size to determine that he belongs at 4.5

He very well may have had some very good matches, and his opponents could very well have had some bad matches ... it happens.

My friend who just got bumped to 4.0 for 2012 went 19-2 in the spirng season and was bumped to 4.5 for 2013. He had a reasonable sample size of matches to determine he was ready to move up .... 4 matches is really not enough, especially when they were all close scores.

schmke 01-22-2013 09:44 AM

Quote:

Originally Posted by ronray43 (Post 7148309)
Still, of the eight opponents he played, all in doubles matches, six of them are rated 4.5 and two rated 4.0. He has proven he's not only competitive as a 4.5, but can win at 4.5. Yet another example of why USTA needs to integrate win-loss record into at least a portion of the NTRP algorithm.

And how do you know that he didn't win because of a strong partner? His rating did improve throughout the year, just not enough to get bumped up.

But, since you want to focus on records, here are his matches.

The first match was a 5 and 4 win over a 4.5 (bumped up from 2011 so not that strong of one) that went 2-4 for the year and finished with a rating just over 4.0 and a 4.0 that only went 5-5 for the year. And he played with a 4.5 partner. So this one wasn't that strong a win.

The second and third matches were with a self-rated partner so they didn't generate a match rating for him, but were a match tie-break win (but lost more games than the opponent) over a 4.5 that went 1-3 for the year and a newly bumped to 4.5 that went 1-4 for the year, and a close 6 and 5 win over a 4.5 that went 0-2 and a 4.0 that went 1-4. Even if these counted, they would not have been that impressive.

The fourth match was a 5 and 4 win over two 4.5s one that went 4-2 but one that went just 1-1. This was the most impressive result for the year and by itself indicated he played at a 4.5 level, and did improve his dynamic rating, but wasn't enough to get his overall rating above 4.0.

So, if you look at the details, you see that he had a winning record, but the matches were all close, two opponents were 4.0s, and two other opponents were just bumped to 4.5 so likely on the lower end of the 4.5 range. And the combined record of his opponents was just 15-25 on top of them not all being 4.5s. And he played with what appears to be a strong partner.

So his staying at 4.0 seems entirely plausible.

LuckyR 01-22-2013 02:14 PM

Quote:

Originally Posted by schmke (Post 7148113)
Perhaps my use of the word flaw was a little strong. It is just how the system behaves when two players partner at doubles all the time. The gap between their ratings will be maintained.

Without some other matches played with other partners and/or singles matches to otherwise adjust one of the individuals ratings, what alternative do you suggest for this situation where matches are always played with the same partner?

You can't just arbitrarily shrink the gap between their ratings as that too many not be correct and may not give the credit due to the higher rated partner. We've just looked at one situation where the big gap seems like an error but I'm sure there are others where a small gap would similarly be an error.

It is just the nature of a system that calculates ratings based on limited data. It isn't perfect, but it is better than many alternatives.


Again, I agree with you that that is how the system works.

Basically the current system has 600 levels (1.00 to 7.00, in 0.01 increments) but from a practical standpoint it lumps them into 10 (1.5 through 6.0-7.0). Thus if your rating change happens to cross particular threshholds you get "bumped up", though your rating has been changing every match you play.

It is my personal opinion, (and I know that many disagree with this) that given the tremendous leeway in the numerous variables that go into why we all win and lose matches: emotions, fatigue, preparation, equipment, surfaces, illness, conditions etc that to assume that it is all matchplay quality and assign 3 significant digits worth of accuracy to each player's quality is naive and simpleminded.

I like the 10 level NTRP system, but I would not have a "secret" behind the scenes rating. I would use either the 10 levels themselves, or at most 2 significant digits worth (1.0 to 7.0, in 0.1 increments).

The world is divided into two types: lumpers and splitters. The USTA are splitters, I'm a lumper. Neither is right or wrong, it's how you look at the world.

J_R_B 01-22-2013 03:06 PM

There was a guy a couple years ago here at 4.0 who played both 4.0 (8-2 including districts/sectionals) and 4.5 (3-1) and got bumped from 4.0 to 4.5. Then he played a year at 4.5, then played another year at 4.5 where he was 5-0, and got bumped back down to 4.0. It was the strangest thing I'd ever seen in the ratings. Of course, he knew he was a 4.5, so kept playing for his 4.5 team and signed up for the 4.0 team that was going to win the league late in the year and played two matches to get eligible and played in the playoffs (then got bumped again). He's currently playing both 4.5 and 5.0, although it's a stretch to say he's a legit 5.0 (more like a league filler since there is a scarcity of real 5.0s here).

schmke 01-22-2013 03:06 PM

Quote:

Originally Posted by LuckyR (Post 7149364)
I like the 10 level NTRP system, but I would not have a "secret" behind the scenes rating. I would use either the 10 levels themselves, or at most 2 significant digits worth (1.0 to 7.0, in 0.1 increments).

I'm a bit confused. The NTRP system does effectively have the 10 levels as there is not a 3.67 level. There is 3.5 and 4.0 and you are one or the other.

But you have to have a way to determine when someone has improved or declined such that they should move into an adjacent level. The NTRP does this through having calculations to the hundredth and established periods at the end of which the rating check and level (re)assignment is done.

In your scenario, how would you calculate when someone should move up or down a level? I think that is what the debate is about, not so much having some reasonable number of levels.

IMHO, you have to go to at a minimum tenths and realistically hundredths to have a reasonable way to calculate ratings based on opponents ratings. Treating all players at a given half-point level the same would not result in an accurate system at all.

You can easily have scenarios where player A, a weak to middle 4.0 plays court 3 and has a good record players just bumped up from 3.5 and gets bumped to 4.5 because he won a lot at 4.0. While player B, a middle to strong 4.0 plays court 1 and loses more than he wins against strong 4.0s just bumped down from 4.5 and gets bumped down to 3.5 because he lost a lot a 4.0. So you have player A, probably not as strong as player B, but A gets bumped up to 4.5 and B down to 3.5, a full 2 levels apart.

wrxinsc 01-22-2013 04:03 PM

Quote:

Originally Posted by schmke (Post 7149501)
I'm a bit confused. The NTRP system does effectively have the 10 levels as there is not a 3.67 level. There is 3.5 and 4.0 and you are one or the other.

But you have to have a way to determine when someone has improved or declined such that they should move into an adjacent level. The NTRP does this through having calculations to the hundredth and established periods at the end of which the rating check and level (re)assignment is done.

In your scenario, how would you calculate when someone should move up or down a level? I think that is what the debate is about, not so much having some reasonable number of levels.

IMHO, you have to go to at a minimum tenths and realistically hundredths to have a reasonable way to calculate ratings based on opponents ratings. Treating all players at a given half-point level the same would not result in an accurate system at all.

You can easily have scenarios where player A, a weak to middle 4.0 plays court 3 and has a good record players just bumped up from 3.5 and gets bumped to 4.5 because he won a lot at 4.0. While player B, a middle to strong 4.0 plays court 1 and loses more than he wins against strong 4.0s just bumped down from 4.5 and gets bumped down to 3.5 because he lost a lot a 4.0. So you have player A, probably not as strong as player B, but A gets bumped up to 4.5 and B down to 3.5, a full 2 levels apart.

i really appreciate your patience and understanding with all of the OMG such and such is such a bunch of bullbunch posts. clearly many have no desire to understand how math works (not to mention how the USTA process dynamic ratings which is simple math). or even how statistics work. it is all cool baby. they can go along with their way.

a wise guy once pointed out to me that all modern human interaction is mathematics and politics.

hopefully those folks are skilled in the later. i doubt it. otherwise why not try to take a minute or two and understand the real way of things before posting bullbunch. oh. right. it is the internet.

press on my aligned one.

OrangePower 01-22-2013 04:34 PM

^^^^

Well, it would be simple math and as such easy to understand if USTA published their algorithm... but of course they don't, and for good reason, so we are all left to speculate on how certain results came to be. Some people's guesses (like schmke) are perhaps more educated and better than others', but ultimately still a guess.

Also, just because the current algorithm kinda works does not mean that it is the most optimal way to calculate ratings. So it is fair game to challenge it. For example, I happen to think that an ELO-based algorithm that adjusts a player's rating after every set would work even better.

schmke 01-22-2013 09:58 PM

Quote:

Originally Posted by OrangePower (Post 7149782)
^^^^

Well, it would be simple math and as such easy to understand if USTA published their algorithm... but of course they don't, and for good reason, so we are all left to speculate on how certain results came to be. Some people's guesses (like schmke) are perhaps more educated and better than others', but ultimately still a guess.

You are right, I'm guessing, but given how accurate I've been in agreeing with bump ups/downs, I think my estimates are pretty accurate.

Quote:

Originally Posted by OrangePower (Post 7149782)
Also, just because the current algorithm kinda works does not mean that it is the most optimal way to calculate ratings. So it is fair game to challenge it. For example, I happen to think that an ELO-based algorithm that adjusts a player's rating after every set would work even better.

I agree that the algorithm is not necessarily the best. I'd certainly do some things different if I was doing it from scratch. Tell me more about updating a rating after every set though. If you were supposed to win a set 6-4 but win 6-2, the participating players ratings are updated and you are supposed to win the 2nd set 6-3 or something like that?


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