WTA Elo Ratings - revised (04/11/2013) - Page 2 - TennisForum.com
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post #16 of 112 (permalink) Old Jun 8th, 2015, 12:36 PM Thread Starter
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Re: WTA Elo Ratings - revised (04/11/2013)

Quote:
Originally Posted by HowardH View Post
Kleinebiere, would you be able to give us your updated ELO ratings?
hmm no updates anymore.

but the current top 30 is...

Code:
1	Serena Williams			2401
2	Maria Sharapova			2200
3	Simona Halep			2126
4	Victoria Azarenka		2122
5	Carla Suarez Navarro		2091
6	Petra Kvitova			2084
7	Caroline Wozniacki		2062
8	Venus Williams			2040
9	Ana Ivanovic			2035
10	Timea Bacsinszky		2022
11	Lucie Safarova			2020
12	Angelique Kerber		1999
13	Karolina Pliskova		1964
14	Garbine Muguruza		1961
15	Ekaterina Makarova		1952
16	Elina Svitolina			1952
17	Agnieszka Radwanska		1940
18	Svetlana Kuznetsova		1937
19	Sloane Stephens			1934
20	Samantha Stosur			1934
21	Sara Errani			1928
22	Flavia Pennetta			1924
23	Jelena Jankovic			1919
24	Andrea Petkovic			1916
25	Madison Keys			1913
26	Sabine Lisicki			1893
27	Eugenie Bouchard		1890
28	Dominika Cibulkova		1887
29	Alize Cornet			1858
30	Anastasia Pavlyuchenkova	1851

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post #17 of 112 (permalink) Old Jun 8th, 2015, 01:02 PM
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Re: WTA Elo Ratings - revised (04/11/2013)

Thanks!
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post #18 of 112 (permalink) Old Jul 1st, 2015, 06:59 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

similar live ranking
best/worst form
movers up/down
surface ranking
top Czech players

Last edited by Flaxa63; Jul 20th, 2015 at 10:38 AM. Reason: update
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post #19 of 112 (permalink) Old Jul 22nd, 2015, 11:09 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

My methodology is simple .. I pick up the historical data and process them.
But I do not use points-system WTA, because I do not accept egalitarian WTA-system of distribution points


Q/A:
I can see that you calculate the "weight" of every tournament based on the ranking of the top 16 players entering the tournament, probably your own rankings, not WTAs?
- using my own rankings not official WTA!!

But how do you translate that weight into points earned for each round, and how the bonus system works?
- thats a system of formulas..
- bonus system = 1=50, 2-5=40, 6-10=30, 11-25=20, 26-50=10, 51-100=5, 101-250=2 and 251-500=1 bonus point

And do you always calculate the weight based on the top 16, regardless of the draw size of the tournament?
- yes always by 16 top players

How do you accumulate points for players, for how long, does your system devalues points over time?
- 52 weeks

Surface rankings
- 3 years old data (grass = 5 yo)

Good form/bad form
- calculating last 9 weeks.. 1 win ATP = 4, Challenger = 2 and Futures = 1 point..


alt ranking
surface ranking
good form/bad form
movers of the week
nation ranking
best tie-breakers
top Czech players
Surface quality - maximum is 40! - every surface = 10
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)

Last edited by Flaxa63; Jul 23rd, 2015 at 09:46 AM. Reason: explanation and update
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post #20 of 112 (permalink) Old Jul 27th, 2015, 04:48 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
$50,000 Sacramento, CA - final
Kalinina - Mestach 46 64 63

alt ranking
surface ranking
good form/bad form
movers of the week
nation ranking
best tie-breakers
top Czech players
Surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)

Last edited by Flaxa63; Jul 27th, 2015 at 05:09 AM. Reason: update
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post #21 of 112 (permalink) Old Aug 1st, 2015, 09:25 PM
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Re: WTA Elo Ratings - revised (04/11/2013)

Great thread!
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post #22 of 112 (permalink) Old Aug 3rd, 2015, 05:32 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
$50,000 Lexington, KY - final
Hibino - Crawford 62 61

alt ranking
surface ranking
good form/bad form
movers of the week
nation ranking
best tie-breakers
top Czech players
Surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)

and something interesting for someone..
MON - Matches
TUE - Matches

Last edited by Flaxa63; Aug 4th, 2015 at 05:24 AM.
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post #23 of 112 (permalink) Old Aug 5th, 2015, 08:23 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
Washington - Pavlyuchenkova - Rybarikova 76 76

alt ranking
surface ranking
good form/bad form
movers of the week
nation ranking
best tie-breakers
top Czech players
Surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)


MON+TUE matches
WED matches

Last edited by Flaxa63; Aug 7th, 2015 at 05:09 PM.
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post #24 of 112 (permalink) Old Aug 10th, 2015, 12:44 PM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
Stanford-final:
Kerber - Pliskova Karolina 63 57 64

alt ranking
surface ranking
good form/bad form
movers of the week (last week)
nation ranking
best tie-breakers
top Czech players
surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)

Last edited by Flaxa63; Aug 13th, 2015 at 08:26 AM.
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post #25 of 112 (permalink) Old Aug 16th, 2015, 09:17 PM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
Toronto-final:
Bencic - Halep 76 67 30 ret.

alt ranking
surface ranking
good form/bad form
movers of the week
nation ranking
best tie-breakers
top Czech players - a new best Czech = Pliskova Karolina
surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)

Last edited by Flaxa63; Aug 16th, 2015 at 09:34 PM.
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post #26 of 112 (permalink) Old Aug 21st, 2015, 09:09 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
Vancouver - R2:
Wickmayer - Glushko 63 63

alt ranking
surface ranking
a good form/a bad form
movers of the week
nation ranking
best tie-breakers
top Czech players - a new best Czech = Pliskova Karolina
surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)
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post #27 of 112 (permalink) Old Aug 24th, 2015, 07:52 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
Cincinnati - final:
S.Williams - Halep 63 76

alt ranking
surface ranking
a good form/a bad form
movers of the week (last)
nation ranking
best tie-breakers
top Czech players
surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)
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post #28 of 112 (permalink) Old Aug 28th, 2015, 08:08 AM
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Re: WTA Elo Ratings - revised (04/11/2013)

last match:
New Haven: QF
Wozniacki - Garcia C. 63 60

alt ranking
surface ranking
a good form/a bad form
movers of the week (last)
nation ranking
best tie-breakers
top Czech players
surface quality
this year points
zero ratio - count of null points of all tournaments (last 52 weeks)
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post #29 of 112 (permalink) Old Aug 31st, 2015, 08:49 PM
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Re: WTA Elo Ratings - revised (04/11/2013)

FiveThirtyEight:

http://fivethirtyeight.com/features/...t-of-all-time/

Quote:

In this case, there were two main choices to make: First, what level of granularity to cover. That is, do we treat each game in a tennis match as its own “match” — thus increasing our sample size, but measuring something very different from overall wins? Or do we treat a match win as a win — regardless of whether it’s 6-0, 6-0; or 6-4, 3-6, 6-7(7), 7-6(3), 70-68? Or do we go set by set? This tradeoff always exists, even in other settings like football or baseball, where margin of victory and run differential are commonly used. The question is always what we gain in prediction strength by using a less accurate but more detailed metric than wins. For this system, we tested and optimized all three, and found that any predictive gains from using sets or games instead of matches were extremely small. While those versions of our system may yet prove to have their uses, we’ve stuck with a match-based system for most of this analysis.

The second choice is how to update ratings after a match. All Elo systems take the difference between the number of wins a player earned and the number of wins expected, and then do something with that number to determine the appropriate adjustment to the player’s rating. The crudest thing to do is to multiply that difference by some constant number, K, where K is chosen empirically to match the context. In chess, a common K for new players is 40, meaning that for each 10 percent above expectation a player ran, she would gain 4 points in Elo per game. For FiveThirtyEight’s NBA Elo, we used a K of 20. Chess uses a K function that depends on the number of games a player has played. This is the approach taken by other Elo variants such as Glicko and Stephenson, which use additional parameters as well.

We tried and tested all these methods extensively but ultimately settled on our own variant (which substantially outperformed the alternatives) in which the multiplier is determined by a function in the form K/((games in player’s dataset+offset)^shape). K is a constant multiplier much like that used by other systems, offset is a small adjustment to keep new players from shooting up or down too much, and shape tells us what shape the curve should take (essentially, the larger the number, the more stable the ratings for players with lots of games). With this structure in place, we simply had to test to see which parameters performed best over our data set. The values we settled on are a K of 250, offset of 5, and shape of 0.4.

This is an empirical approximation of what this adjustment curve should look like, and can likely be improved with a more accurate function or by incorporating more inputs than games and performance, but we tried to keep it as simple as possible to avoid the potential for overfitting. (The data we used is parsed from that on Jeff Sackmann’s GitHub page, totalling more than 250,000 matches at the tour level).
Thoughts? Would love to see this thread updated.
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post #30 of 112 (permalink) Old Sep 1st, 2015, 02:34 PM Thread Starter
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Re: WTA Elo Ratings - revised (04/11/2013)

Quote:
Originally Posted by jay holter View Post
FiveThirtyEight:

http://fivethirtyeight.com/features/...t-of-all-time/



Thoughts? Would love to see this thread updated.
I have Serena peaking in january 2014. But my variant is simpler. No offset & shape...
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