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View Full Version : Another USTA Stink. Dynamic Rating computer doesn't account individual ability.


Fedace
07-22-2009, 02:50 PM
WOW, today i found out another Fopah by USTA ratings computer. When you play Doubles, computer doesn't account for the weak record of your partner. Direct quote from USTA "the system just looks at the statistical rating of the opponents and makes an evaluation based on how close the match was and what everyone's rating is".


So this means you could play with a statistically very WEAK level 4.5 partner and play against Solid doubles duo that is rated 4.5 and get killed, and it will fault you just as much as your weak partner. This is totally stupid, cause in doubles it happens that sometimes you end up with a very weak partner even though your partner has same rating as you.

There has to be a way in doubles rating to be able to account for the fact that you played a statiscally very weak player. :?:twisted:

Fedace
07-22-2009, 03:17 PM
So how do you handle it if you end up with a partner that is significantly weaker than you and the guy gets picked on all day long. ??

SlapShot
07-22-2009, 03:28 PM
So how do you handle it if you end up with a partner that is significantly weaker than you and the guy gets picked on all day long. ??

You behave like an adult and ask your captain to find a doubles partner that is more compatible with your style of play....?

Fedace
07-22-2009, 03:31 PM
You behave like an adult and ask your captain to find a doubles partner that is more compatible with your style of play....?

Good idea but this year i ended up with a team that sucks, only has 1 player that is decent doubles player. I am playing on this team this year as a favor to the captain who is a friend of mine from high school days. He organized a new team and asked me to play and help out, so i did, being a nice guy i am. :???:

Klaus
07-22-2009, 04:27 PM
Behave like an adult, honor your committment, and make the best of it. Who cares what the computer does? You know what your quality as a player is, and I am guessing those who know you have been told what your abilities are.

After this, just stick to singles so you don't have to worry about the abilities of those beside you on the court. Chalk it up to valuable life experience and move on. It does not sound like doubles league is for you.

Best, Klaus

P.S. It's "faux pas," not "fopah." Just FYI.

JavierLW
07-22-2009, 04:41 PM
WOW, today i found out another Fopah by USTA ratings computer. When you play Doubles, computer doesn't account for the weak record of your partner. Direct quote from USTA "the system just looks at the statistical rating of the opponents and makes an evaluation based on how close the match was and what everyone's rating is".


So this means you could play with a statistically very WEAK level 4.5 partner and play against Solid doubles duo that is rated 4.5 and get killed, and it will fault you just as much as your weak partner. This is totally stupid, cause in doubles it happens that sometimes you end up with a very weak partner even though your partner has same rating as you.

There has to be a way in doubles rating to be able to account for the fact that you played a statiscally very weak player. :?:twisted:

Who in the USTA told you this? (the USTA is not a person, it's an organization)

When they first came out with DNTRP I did some studying of various details that they would give us, and one of them was that they claimed that they considered your partner's rating.

They wont give out the formula so it's doubtful you talked to anyone of meaning that even knows what they are talking about.

Only like District chairs and up probably know even what the ratings are, and even they dont have the exact computer formula because they are likely not IT people.

If you're playing with a weak player, there isnt much you can do about it.

Just make sure you keep your head about you and play your best game, and count "success" as whether you can successfully do that or not, not whether you win. (because winning is even less under your control in doubles then it is in singles, you have 3 people who can mess things up for you now)

If your partner is at least able to block balls back at the net, then put them there. It's sometimes harder to pick on someone when a ball right at them at the net is going to just get blocked back.

(and it's easier for you to control the court from the backcourt)

If your partner cant even do that, then forget about it, you're toast, you're playing doubles you need to have some volleying skill. (if he moves back then you can be sure you will never see that ball and they will truely pick on him even more)

kylebarendrick
07-22-2009, 04:59 PM
From what I recall (and you can look it up on the USTA website about dynamic NTRP), the system maintains the rating difference between you and your partner.

In your case if you are a strong 4.5 (say 4.40) and your partner is weaker (4.10) then your total rating (8.5) would be compared to your opponents total (say 9.0 for two top level 4.5s) when making adjustments based on the match score. In this case the computer would see a 0.5 rating difference between the teams and expect you to lose routinely. Any rating adjustment (assuming you actually lost routinely) would then be small and you and your partner would remain 0.3 apart.

Fedace
07-22-2009, 08:08 PM
Who in the USTA told you this? (the USTA is not a person, it's an organization)

When they first came out with DNTRP I did some studying of various details that they would give us, and one of them was that they claimed that they considered your partner's rating.

They wont give out the formula so it's doubtful you talked to anyone of meaning that even knows what they are talking about.

Only like District chairs and up probably know even what the ratings are, and even they dont have the exact computer formula because they are likely not IT people.

If you're playing with a weak player, there isnt much you can do about it.

Just make sure you keep your head about you and play your best game, and count "success" as whether you can successfully do that or not, not whether you win. (because winning is even less under your control in doubles then it is in singles, you have 3 people who can mess things up for you now)

If your partner is at least able to block balls back at the net, then put them there. It's sometimes harder to pick on someone when a ball right at them at the net is going to just get blocked back.

(and it's easier for you to control the court from the backcourt)

If your partner cant even do that, then forget about it, you're toast, you're playing doubles you need to have some volleying skill. (if he moves back then you can be sure you will never see that ball and they will truely pick on him even more)

That quote came directly from local USTA district coordinator... Yea, my partner had some really weak volleying skills. The trouble with him is that he thinks in doubles, All Volleys have to be hit like a Rocket. So he tries to hit all Volleys really hard, even the Really LOW tough ones..... guess he has been watching the Bryan bros too much.....

Fedace
07-22-2009, 08:10 PM
Behave like an adult, honor your committment, and make the best of it. Who cares what the computer does? You know what your quality as a player is, and I am guessing those who know you have been told what your abilities are.

After this, just stick to singles so you don't have to worry about the abilities of those beside you on the court. Chalk it up to valuable life experience and move on. It does not sound like doubles league is for you.

Best, Klaus

P.S. It's "faux pas," not "fopah." Just FYI.

LOL,,,thanks for the Correction. thats a good one. I can't play singles,,,NOT with this Plantar Fascitis. If i play singles, it feels like i am setting back the healing process by a month. :(

raiden031
07-22-2009, 08:13 PM
From what I recall (and you can look it up on the USTA website about dynamic NTRP), the system maintains the rating difference between you and your partner.

In your case if you are a strong 4.5 (say 4.40) and your partner is weaker (4.10) then your total rating (8.5) would be compared to your opponents total (say 9.0 for two top level 4.5s) when making adjustments based on the match score. In this case the computer would see a 0.5 rating difference between the teams and expect you to lose routinely. Any rating adjustment (assuming you actually lost routinely) would then be small and you and your partner would remain 0.3 apart.

Correct. So the question is this. Is it fair to say that both partners are equally responsible for the outcome in the match such that both of their ratings are adjusted by the exact same amount in order to maintain the 0.3 differential between them? Or should the adjustment of each player's rating be weighted based on their prior rating? That would mean that if the pair's rating goes down, the lower player should bare the brunt of more of the loss in rating, whereas if they go up, the higher rated player should benefit more.

Fedace
07-22-2009, 08:14 PM
From what I recall (and you can look it up on the USTA website about dynamic NTRP), the system maintains the rating difference between you and your partner.

In your case if you are a strong 4.5 (say 4.40) and your partner is weaker (4.10) then your total rating (8.5) would be compared to your opponents total (say 9.0 for two top level 4.5s) when making adjustments based on the match score. In this case the computer would see a 0.5 rating difference between the teams and expect you to lose routinely. Any rating adjustment (assuming you actually lost routinely) would then be small and you and your partner would remain 0.3 apart.

REALLY,,, from what the district coordinator told me, it sure didn't sound like that was the case. but i think you make alot of sense. From what i was told, Computer doesn't have the capability to distinguish among the 4.5's like 4.1 vs 4.4 and so on.??? :confused: I sure hope what you are saying is True. If so, i don't have to worry as much about playing with a Weaker partner.... Who told you about this ?? thanks.

Fedace
07-22-2009, 08:17 PM
Correct. So the question is this. Is it fair to say that both partners are equally responsible for the outcome in the match such that both of their ratings are adjusted by the exact same amount in order to maintain the 0.3 differential between them? Or should the adjustment of each player's rating be weighted based on their prior rating? That would mean that if the pair's rating goes down, the lower player should bare the brunt of more of the loss in rating, whereas if they go up, the higher rated player should benefit more.

You make alot of sense as well. but I don't think the Computers USTA is smart enough to do this. I think you need one of those Super computers that Pentagon has in order to give it a capability to do this....:):(

raiden031
07-22-2009, 08:21 PM
You make alot of sense as well. but I don't think the Computers USTA is smart enough to do this. I think you need one of those Super computers that Pentagon has in order to give it a capability to do this....:):(

I actually think what the USTA does is most fair. Since you don't know which player had more impact on the outcome of the match, you assume that both contributed equally (with respect to their original rating) and retain the original differential.

Actually I think simply separating singles and doubles ratings would make the system more accurate, but it would be more complex and a nightmare to manage, especially when you end up with players having like a 3.5 singles rating and 4.0 doubles rating. I think it would be interesting to see though.

10sfreak
07-22-2009, 08:23 PM
WOW, today i found out another Fopah by USTA ratings computer. When you play Doubles, computer doesn't account for the weak record of your partner. Direct quote from USTA "the system just looks at the statistical rating of the opponents and makes an evaluation based on how close the match was and what everyone's rating is".


So this means you could play with a statistically very WEAK level 4.5 partner and play against Solid doubles duo that is rated 4.5 and get killed, and it will fault you just as much as your weak partner. This is totally stupid, cause in doubles it happens that sometimes you end up with a very weak partner even though your partner has same rating as you.

There has to be a way in doubles rating to be able to account for the fact that you played a statiscally very weak player. :?:twisted:
Fedace, wouldn't the fact that the word, "everyone's", mean that your weak partner's rating would also be considered?

Fedace
07-22-2009, 08:24 PM
^^^I think in the future, USTA will have to have singles and doubles ratings. That would be most fair. I know guys that are Killer 4.5 doubles players that if you put them on the singles court, they get beat by mid range 4.0 player. As the Computers get smarter and faster, i think it can easily be done.

Fedace
07-22-2009, 08:26 PM
Fedace, wouldn't the fact that the word, "everyone's", mean that your weak partner's rating would also be considered?

Yes, you would think that. but when i asked specifically, "Does the computer account for the fact that you played with a weak partner??", the district coordinator said "No". so i was a bit confused as well.

todd03blown
07-22-2009, 08:43 PM
As the Computers get smarter and faster, i think it can easily be done.

I am not sure if this is a serious post??

computers are more than certainly fast enough to handle processing tennis ratings to include your wishlist of having a doubles and singles rating. It all comes down the developer writing the code to get this to work...Hell computers today process hundreds of millions of records in seconds so a little old individual tennis rating is a walk in park and it won't even break a sweat!

Jim A
07-22-2009, 08:53 PM
good NTRP article in the Coloradotennis.com mag this month...go to the site and find it Fedace...discusses stuff like your comments in detail...

kylebarendrick
07-22-2009, 10:50 PM
REALLY,,, from what the district coordinator told me, it sure didn't sound like that was the case. but i think you make alot of sense. From what i was told, Computer doesn't have the capability to distinguish among the 4.5's like 4.1 vs 4.4 and so on.??? :confused: I sure hope what you are saying is True. If so, i don't have to worry as much about playing with a Weaker partner.... Who told you about this ?? thanks.
From the USTA website here: http://www.usta.com/USTA/Global/Active/Custom%20Pages/Leagues/~/media/USTA/Document%20Assets/Leagues_and_Tournaments/Leagues/How%20Dyanmic%20Ratings%20are%20Calculated%20for%2 0a%20Specific%20Match.ashx
===========================
How Dyanmic Ratings are Calculated for a Specific Match
In matches where all players have previous ratings the procedure is as follows:
1. The system looks up the current dynamic rating of all the players in the match.
2. The system looks up from a table, the likely score of the match based on the current dynamics of the
players.
3. The system compares the likely match score with the actual match score. For example, if one player or
team has a tenth of a point higher rating than the opponent, the likely score is 6-4, 6-4.
• If the winning team wins by a larger than expected margin, each player’s ratings is increased based
on the margin of victory and the losing player’s rating is decreased by the same amount.
• If the winning team wins by less than the expected margin, their ratings will actually decrease and
the losing team’s ratings will increase.
• Likewise, the “wrong” team may win which causes their rating to increase markedly and the rating
of the team which was favored would decrease by the same amount.
4. The rating obtained for each player in Step #3 is averaged with a maximum of their previous three
dynamic ratings and that number becomes their new current dynamic rating. (Indirectly this connects the
current dynamic to all previous matches but weights the four most recent matches more heavily.) The
reason for this averaging is to even out the ratings in cases where some unusual situation causes an
atypical result.
Each player rating is maintained in the system to the nearest hundredth of a point.
The difference in ratings of the members of a doubles team is held constant in a calculation of an individual
match. If the two players are three hundredths (.03) of a point apart going into the match then they are three
hundredths (.03) apart after the calculation in Step #4. However, once that number is averaged with the
three previous dynamic ratings (Step #5) that difference may change. This is how we measure the
performance of players as they change partners.

Fedace
07-23-2009, 02:53 AM
^^^GREAT post Kyle. Thank you.

goober
07-23-2009, 07:08 AM
^^^I think in the future, USTA will have to have singles and doubles ratings. That would be most fair. I know guys that are Killer 4.5 doubles players that if you put them on the singles court, they get beat by mid range 4.0 player. As the Computers get smarter and faster, i think it can easily be done.

Computers from more than 15 years ago, could easily handle this type of calculation. USTA doesn't have seperate ratings because it chooses not to, not because of a lack of computing power- lol.

"Fopah"- that's a good one. You don't know the term or the correct usage, so you made up a word the sounds phonetically close. Thanks for the chuckle :)

Cindysphinx
07-23-2009, 09:27 AM
Correct. So the question is this. Is it fair to say that both partners are equally responsible for the outcome in the match such that both of their ratings are adjusted by the exact same amount in order to maintain the 0.3 differential between them? Or should the adjustment of each player's rating be weighted based on their prior rating? That would mean that if the pair's rating goes down, the lower player should bare the brunt of more of the loss in rating, whereas if they go up, the higher rated player should benefit more.

I think this idea is based on an assumption that does not always hold: That the weaker player was more responsible for the loss, and the stronger player was more responsible for the win.

I have had times when I was the weaker player and I played great, but my "stronger" partner was messing up right and left and dragged us down. I have also had times when I was the stronger player and I couldn't do a single thing right.

I've also had times when my weaker partner dug deep and, for that one match, played way above her normal level of play.

Surely we can't expect the computer to account for the unexpected, right? Isn't the best solution to assume both players played at their normal level? And if you make that assumption, wouldn't you hold the differential between them constant?

raiden031
07-23-2009, 09:56 AM
I think this idea is based on an assumption that does not always hold: That the weaker player was more responsible for the loss, and the stronger player was more responsible for the win.

I have had times when I was the weaker player and I played great, but my "stronger" partner was messing up right and left and dragged us down. I have also had times when I was the stronger player and I couldn't do a single thing right.

I've also had times when my weaker partner dug deep and, for that one match, played way above her normal level of play.

Surely we can't expect the computer to account for the unexpected, right? Isn't the best solution to assume both players played at their normal level? And if you make that assumption, wouldn't you hold the differential between them constant?

I think it is the best solution. Fedace's OP led me to believe that he thinks the weaker player should be punished more for a bad loss. Maybe he doesn't know enough about how the rating system generates ratings after a doubles match and was misled by what the coordinator told him.

Nellie
07-23-2009, 11:52 AM
My question has to do with mixed leagues in which there can be a really great division between the partners (at least 1 whole NTRP point), like a 5.0/4.0 combo playing and winning at 9.0 mixed against 4.5 pairs.

With teams where each of the players has a mixed exclusive rating, I repeatedly see instances where the stronger player, despite despite winning virtually every match will be moved down and and the weaker player moved up. So, I am trying to gain some insight into the algorithm of the computer as to why this occurs.

Fedace
07-23-2009, 04:17 PM
I think this idea is based on an assumption that does not always hold: That the weaker player was more responsible for the loss, and the stronger player was more responsible for the win.

I have had times when I was the weaker player and I played great, but my "stronger" partner was messing up right and left and dragged us down. I have also had times when I was the stronger player and I couldn't do a single thing right.

I've also had times when my weaker partner dug deep and, for that one match, played way above her normal level of play.

Surely we can't expect the computer to account for the unexpected, right? Isn't the best solution to assume both players played at their normal level? And if you make that assumption, wouldn't you hold the differential between them constant?

We are Not as interested in what happens unexpectedly. We are interested in what happens 90% of the time. and yes differential should be held constant. and yes the weaker player should take more of the penalty for the loss than the stronger player.

OrangePower
07-23-2009, 04:35 PM
We are as interested in what happens unexpectedly. We are interested in what happens 90% of the time. and yes differential should be held constant. and yes the weaker player should take more of the penalty for the loss than the stronger player.

Sorry I just don't get your point of view. The way the USTA algorithm works is very logical. First off, it uses dynamic ratings (meaning, not just 4.0 or 4.5, but more detailed than that). So a weak 4.5 has a lower dynamic rating than a strong 4.5. Then it takes the sum of the dynamic ratings of you and your partner, and then compares that against the sum of the ratings of your opponents. Then it sees how you actually did, versus how it predicts you were expected to do based on the ratings.

Lets say that you and your partner did not do as well as expected. Both partners take an equal share of the blame for it (and an equal ratings hit). Without actually watching the match, that's the best you can do.

Does that mean the computer thinks you played equally well in absolute terms? No. But it does mean the computer thinks you played equally well relative to your ratings. Meaning that if you are a strong 4.5, and your partner is a weak 4.5, the computer says that you did not play up to the level of a strong 4.5, and your partner did not play up to the level of a weak 4.5.

raiden031
07-23-2009, 04:44 PM
We are as interested in what happens unexpectedly. We are interested in what happens 90% of the time. and yes differential should be held constant. and yes the weaker player should take more of the penalty for the loss than the stronger player.

You can't have it both ways. In order for the differential between partners to remain constant, then both the weaker and stronger player must take the same rating hit.

Fedace
07-23-2009, 04:47 PM
You can't have it both ways. In order for the differential between partners to remain constant, then both the weaker and stronger player must take the same rating hit.

Weaker guy should get 90 % of the hit in my opinion if you lose. If you win, you can both get same amount of credit. That is only fair and a price you have to pay if you play with better player.

Cindysphinx
07-23-2009, 06:47 PM
Weaker guy should get 90 % of the hit in my opinion if you lose. If you win, you can both get same amount of credit. That is only fair and a price you have to pay if you play with better player.

Um . . .

The computer is not dividing up prize money between doubles partners. It is trying to measure the performance of one pair against the performance of the other.

I don't understand why on earth the lower-rated player should have her rating tank because she and her partner lost or underperformed. The higher-rated player presumably had stronger tennis skills. If anyone should have stepped up, why shouldn't it be the stronger-rated player?

Anyway, in this hypothetical match in which the weaker player takes 90% of the hit, what happens to the other team that beat them? Who gets the credit on that opposing team -- the weaker or stronger player?

Fedace
07-23-2009, 06:51 PM
Um . . .

The computer is not dividing up prize money between doubles partners. It is trying to measure the performance of one pair against the performance of the other.

I don't understand why on earth the lower-rated player should have her rating tank because she and her partner lost or underperformed. The higher-rated player presumably had stronger tennis skills. If anyone should have stepped up, why shouldn't it be the stronger-rated player?

Anyway, in this hypothetical match in which the weaker player takes 90% of the hit, what happens to the other team that beat them? Who gets the credit on that opposing team -- the weaker or stronger player?

Winning team gets Equal credit for both partners, that is only the fair way.