|01-07-2013, 03:04 PM||#42|
Join Date: Dec 2006
Is that the one you meant?
The UE were not too different (Fed 28, Tomic 32), but Federer had a massive lead in winners.
Yeah, that's one reason I prefer posting in this sub-forum even when mostly talking about current players (but at some point in this thread hopefully we can talk more about former players' stats).
|01-07-2013, 04:40 PM||#43|
Join Date: Dec 2006
Other great performances.
Cash - 42.9%
Lendl - 29.7%
Kuerten - 41.4%
Mirnyi - 37.9%
Isner - 39.4%
Mahut - 41.9%
Gasquet - 35.5%
Roddick - 31.2%
Kohlschreiber - 34.6%
Roddick - 32.6%
Roddick - 33.9%
El Aynaoui - 30.6%
Philippoussis - 29.8%
Sampras - 25.4%
Last edited by krosero : 01-07-2013 at 07:22 PM.
|01-07-2013, 05:31 PM||#44|
Join Date: Jul 2008
Super thread Krosero. Thanks.
A couple more:
2001 US Open Final
Sampras - 34.6%
Agassi - 30.5%
1991 US Open Final
Edberg - 36.9%
Courier - 14.6%
Last edited by corners : 01-07-2013 at 05:41 PM.
|01-07-2013, 06:24 PM||#45|
Join Date: Dec 2006
Ratios for Federer against Nadal at Wimbledon:
2006 – 3.34
2007 – 4.15
2008 – 3.40
Ratios for Nadal against Federer at Wimbledon:
2006 – 3.12
2007 – 5.17
2008 – 5.81
Yesterday we were debating whether to use margins or ratios. We talked a lot about winner/error ratios, but I wondered what would happen if I used the broader category of Aggressive Points rather than just the Winners that are usually reported in the media. Aggressive Points are all the points a player wins either by striking clean winners or forcing his opponent into errors.
Above are the resulting ratios for Nadal and Federer and Wimbledon. For example, in the 2006 final, Federer's Aggressive Points were 3.34 times more numerous than his unforced errors.
But the ratios do not reflect the results accurately. Federer's ratio is just slightly better than Nadal's in 2006, implying a tight victory, when in fact it was a four-setter.
Nadal barely won the 2008 match, 9-7 in the fifth, but his ratio is much larger than Federer's, implying an easy victory.
Finally in 2007, Nadal lost the match but he has a higher ratio than Federer.
When I sorted all my data in Excel according to ratios, some strange things came up.
The best example is Wilander's five-set loss to Sampras at the 1989 USO. Wilander had an Aggressive Margin of 29.8%. That was #74 among all the AM's I had calculated, that is, the 74th highest AM.
But when ratios are used, Wilander's performance jumps to the 5th best performance in all my data. His ratio of Aggressive Points to UE is 12.38. It's not only better than Sampras' performance in the same match (Pete drops down to #110 on the list, with a ratio of just 2.88 ). Wilander's performances also looks better, by this measure, than any performance by Federer, Sampras, Nadal or Djokovic.
The reason is that Wilander made only 8 unforced errors in that match. Nobody was better at keeping his unforced errors down.
And if you have your UE's down in the single digits, you're going to generate extremely high ratios of Aggressive Points to UE's. It's easy to see why: if you make 50 Aggressive Points and 2 UE's, your ratio is 25.0. Drop down just 1 UE, and your ratio jumps to 50.0.
Sampras/Wilander was the most extreme example, but there were others. It's clear that ratios disproportionately favor great defenders, and give inaccurate pictures of results.
The Aggressive Margin, by contrast, has Sampras at 31.5%, Wilander at 29.8%, an accurate representation of Pete's narrow five-set victory.
Anyway, I'll get back to posting more AM's -- I have several more now, including some very high ones for Nadal.
|01-07-2013, 07:16 PM||#46|
Join Date: Dec 2006
I've added new numbers to my opening post for the following:
Nadal/Djokovic 2008 RG
Nadal/Almagro 2008 RG
Nadal/Youzhny 2008 Wimbledon
Safin/Djokovic 2008 Wimbledon
Federer/Safin 2008 Wimbledon
Federer/Delpo 2009 AO
Nadal/Gonzalez 2009 AO
Federer/Delpo 2009 RG
Federer/Haas 2009 RG
Hewitt/Delpo 2009 Wimbledon
Federer/Karlovic 2009 Wimbledon
Roddick/Murray 2009 Wimbledon
Federer/Karlovic 2012 AO
Federer/Tomic 2012 AO
Nadal/Ferrer 2012 RG
I’ve also created new lists for Roddick, Hewitt, Safin, Del Potro, Tsonga.
Last edited by krosero : 02-12-2013 at 12:38 PM.
|01-07-2013, 07:17 PM||#47|
Join Date: Dec 2006
These are the highest Aggressive Margins I’ve calculated for Federer:
2008 AO, R128, d. Santoro - 50.0%
2004 Wimb R128, d. Bogdanovic - 48.7%
2011 WTF round robin, d. Nadal - 48.2%
2012 Wimb R64, d. Fognini - 48.1%
2004 Wimb R64, d. Falla - 45.9%
2008 Wimb QF, d. Ancic - 45.8%
2006 Wimb R64, d. Henman - 44.7%
2006 Wimb R128, d. Gasquet - 44.6%
2003 Wimb sf, d. Roddick - 44.3%
2012 Wimb R128, d. Ramos - 43.4%
2009 Wimb qf, d. Karlovic - 42.5%
2003 Wimb final, d. Philippoussis - 42.1%
2009 AO qf, d. Del Potro - 42.0%
2003 Wimb qf, d. Schalken - 41.8%
2005 Wimb final, d. Roddick - 41.7%
2007 AO sf, d. Roddick - 41.4%
2004 Wimb R32, d. Johansson - 41.2%
2011 Wimb R32, d. Nalbandian - 40.8%
2011 Wimb qf, lost to Tsonga - 40.1%
2006 Wimb sf, d. Bjorkman - 39.8%
2004 Wimb R16, d. Karlovic - 39.8%
2003 Wimb R32, d. Fish - 39.6%
2012 Wimb R16, d. Malisse - 39.4%
2006 Wimb R32, d. Mahut - 39.2%
2012 Wimb sf, d. Djokovic - 38.4%
2009 AO sf, d. Roddick - 37.9%
2012 Wimb qf, d. Youzhny - 37.8%
2006 USO final, d. Roddick - 37.3%
2006 Wimb QF, d. Ancic - 37.1%
2001 Wimb R16, d. Sampras - 37.0%
2006 Wimb R16, d. Berdych - 36.9%
2003 Wimb R16, d. Lopez - 36.8%
2005 Wimb qf, d. Gonzalez - 35.8%
2007 Wimb sf, d. Gasquet - 35.8%
2004 Wimb qf, d. Hewitt - 35.2%
2008 Wimb R16, d. Hewitt - 35.1%
2009 Wimb final, d. Roddick - 34.9%
2005 USO R64, d. Santoro - 34.6%
2012 Wimb R32, d. Benneteau - 34.6%
2005 Wimb R16, d. Ferrero - 34.4%
2005 AO R128, d. Santoro - 34.3%
2007 AO final, d. Gonzalez - 34.3%
2009 RG, R16, d. Haas - 33.8%
2007 USO qf, d. Roddick - 33.3%
2007 USO R32, d. Isner - 33.3%
2008 Wimb sf, d. Safin - 33.3%
2007 Wimb final, d. Nadal - 33.1%
2012 AO, R32, d. Karlovic - 33.0%
2008 Wimb R64, d. Soderling - 32.4%
2010 AO sf, d. Tsonga - 32.4%
2004 USO sf, d. Henman - 32.3%
2008 AO R16, d. Berdych - 32.1%
2010 AO R16, d. Hewitt - 31.8%
2010 Wimb qf, lost to Berdych - 31.4%
2007 Wimb R32, d. Safin - 31.4%
2005 Wimb R32, d. Kiefer - 31.4%
2004 Wimb final, d. Roddick - 31.4%
2005 Wimb sf, d. Hewitt - 31.1%
2004 USO final, d. Hewitt - 31.1%
2007 Masters Cup sf, d. Nadal - 31.0%
2004 Wimb sf, d. Grosjean - 31.0%
2005 Wimb R64, d. Minar - 30.9%
2009 RG final, d. Soderling - 30.6%
2012 Wimb final, d. Murray - 30.1%
2004 AO sf, d. Ferrero - 30.5%
2006 Wimb final, d. Nadal - 30.5%
2012 London Olympics sf, d. Del Potro - 30.3%
2008 Wimb final, lost to Nadal - 30.3%
2012 Davis Cup, lost to Isner - 30.1% (Isner 32.5%)
2003 Wimb R64, d. Koubek - 29.7%
2005 USO qf, d. Nalbandian - 29.5%
2006 USO sf, d. Davydenko - 29.5%
2009 RG sf, d. Del Potro - 29.0%
2008 RG sf, d. Monfils - 29.0%
2006 USO R64, d. Henman - 28.9%
2007 Wimb R64, d. Del Potro - 28.8%
2005 Wimb R128, d. Mathieu - 28.7%
2012 AO qf, d. Del Potro - 28.7%
2006 USO R32, d. Spadea - 28.2%
2005 USO final, d. Agassi - 28.2%
2006 Masters Cup final, d. Blake - 28.1%
2006 USO qf, d. Blake - 27.8%
2013 AO R32, d. Tomic - 27.3%
2005 AO qf, d. Agassi - 27.0%
2007 AO R128, d. Phau - 26.9%
2010 USO sf, d. Youzhny - 26.6%
2011 Davis Cup (grass), d. Hewitt - 26.4%
2007 AO R16, d. Djokovic - 25.4%
2010 WTF final, d. Nadal - 25.4%
2007 USO sf, d. Davydenko - 25.2%
2009 AO R16, d. Berdych - 24.8%
2005 USO sf, d. Hewitt - 24.8%
2011 RG sf, d. Djokovic - 24.3%
2008 AO R32, d. Tipsarevic - 24.3%
2008 USO sf, d. Djokovic - 24.1%
2012 AO, R16, d. Tomic - 24.0%
2009 USO sf, d. Djokovic - 23.7%
2009 AO R32, d. Safin - 23.5%
2012 RG qf, d. Del Potro - 23.1%
2004 AO R16, d. Hewitt - 23.0%
2004 USO R32, d. Santoro - 22.0%
2012 Indian Wells sf, d. Nadal - 21.4%
2004 AO final, d. Safin - 21.4%
2005 Masters Cup sf, d. Gaudio - 21.3%
2010 RG qf, lost to Soderling - 21.2% (Soderling at 22.5%)
2005 AO sf, lost to Safin - 20.8%
2008 USO final, d. Murray - 20.4%
2007 USO final, d. Djokovic - 20.3%
2009 AO R64, d. Korolev - 20.3%
2012 USO qf, lost to Berdych - 20.0%
2009 AO final, lost to Nadal - 19.9%
2013 AO qf, d. Tsonga - 18.3%
2009 Madrid final, d. Nadal - 18.2%
2008 AO sf, lost to Djokovic - 18.0%
2006 AO final, d. Baghdatis - 17.8%
2004 USO qf, d. Agassi - 17.7% (Agassi at 19.0%)
2010 AO final, d. Murray - 17.6%
The highest AM’s I’ve calculated for Nadal:
2008 Wimb qf, d. Murray - 44.6%
2006 Wimb, R32, d. Agassi - 41.2%
2009 AO R32, d. Haas - 40.6%
2011 Wimb R64, d. Sweeting - 40.2%
2011 Wimb R32, d. Muller - 40.2%
2008 Wimb R16, d. Youzhny - 40.0%
2011 Wimb qf, d. Fish - 37.7%
2011 Wimb R16, d. Del Potro - 37.3%
2009 AO R64, d. Karanusic - 36.9%
2011 W R128, d. Russell - 36.2%
2006 Wimb R64, d. Kendrick - 35.9%
2012 RG, R16, d. Monaco - 35.7%
2006 Wimb sf, d. Baghdatis - 35.1%
2007 Wimb R64, d. Youzhny - 35.0%
2009 AO R128, d. C. Rochus - 35.0%
2010 Wimb sf, d. Murray - 34.9%
2008 RG final, d. Federer - 34.7%
2008 Wimb sf, d. Schuettler - 34.2
2011 USO qf, d. Roddick - 34.1%
2011 Wimb sf, d. Murray - 33.3%
2012 Wimb R64, lost to Rosol - 33.3% (Rosol at 34.1%)
2012 RG, R64, d. Istomin - 32.5%
2008 RG sf, d. Djokovic - 32.3%
2010 Wimb qf, d. Soderling - 32.2%
2010 Wimb final, d. Berdych - 32.2%
2008 Wimb final, d. Federer - 31.5%
2011 Wimb final, lost to Djokovic - 31.1%
2007 Wimb final, lost to Federer - 31.0%
2009 AO R16, d. Gonzalez - 30.9%
2008 RG qf, d. Almagro - 30.8%
2011 RG, R32, d. Veic - 30.3%
2007 Wimb qf, d. Berdych - 29.9%
2008 RG, R16, d. Verdasco - 28.8%
2007 RG sf, d. Djokovic - 28.7%
2010 Wimb R128, d. Nishikori - 27.9%
2010 USO R16, d. Lopez - 27.4%
2007 USO R32, d. Tsonga - 27.3%
2011 Davis Cup (clay), d. Tsonga - 26.8%
2009 USO R128, d. Gasquet - 26.3%
2011 RG qf, d. Soderling - 26.1%
2011 RG, R128, d. Isner - 26.1%
2008 Miami qf, d. Blake - 25.4%
2010 USO qf, d. Verdasco - 25.4%
2008 RG, R64, d. Devilder - 25.2%
2012 RG sf, d. Ferrer - 24.4%
2007 RG qf, d. Moya - 24.2%
2010 USO R128, d. Gabashvili - 24.1%
2009 AO sf, d. Verdasco - 23.9%
2010 USO R64, d. Istomin - 23.9%
2012 AO R64, d. Haas - 23.6%
2007 Wimb R32, d. Soderling - 23.4%
2012 AO qf, d. Berdych - 23.4%
2005 RG final, d. Puerta - 23.4%
2010 USO final, d. Djokovic - 22.8%
2011 RG sf, d. Murray - 22.4%
2006 Wimb final, lost to Federer - 22.4%
2007 AO qf, lost to Gonzalez - 22.2%
2009 MC final, d. Djokovic - 22.1%
2011 RG final, d. Federer - 22.0%
2010 RG final, d. Soderling - 21.6%
2009 AO qf, d. Simon - 21.3%
2007 AO, R16, d. Murray - 21.3%
2009 USO qf, d. Gonzalez - 21.1%
2005 Madrid final, d. Ljubicic - 21.1%
2005 RG, qf, d. Ferrer - 20.9%
2011 USO sf, d. Murray - 20.7%
2007 RG, R64, d. Cipolla - 20.7%
2008 USO R32, d. Troicki - 20.1%
2008 Hamburg final, d. Federer - 20.1%
2008 AO R32, d. Simon - 20.0%
2009 AO final, d. Federer - 19.6%
2005 USO R32, lost to Blake - 19.1%
2007 RG final, d. Federer - 18.8%
2006 RG final, d. Federer - 18.3%
2012 RG final, d. Djokovic - 17.8%
2012 AO sf, d. Federer - 17.8%
2009 RG R16, lost to Soderling - 15.1% (Soderling’s figure was 20.7%)
2011 WTF round-robin, lost to Federer - 14.8%
2010 Madrid final, d. Federer - 14.8%
2010 USO R32, d. Simon - 14.4%
2009 Madrid final, lost to Federer - 14.1%
2007 Rome sf, d. Davydenko - 13.9%
2005 AO R16, lost to Hewitt - 13.7%
2011 Miami sf, d. Federer - 13.6%
2005 RG, R32, d. Gasquet - 13.2%
2005 RG sf, d. Federer - 13.0%
Last edited by krosero : 08-09-2013 at 05:45 AM.
|01-07-2013, 07:59 PM||#48|
Join Date: Dec 2006
I did a list of Sampras-Agassi AM's some years back: http://tt.tennis-warehouse.com/showt...25#post2862325.
I have very little for Edberg and Courier. Just these:
1989 Masters Cup final
Edberg - 24.7%
Becker - 22.6%
Courier - 24.4%
Sampras - 14.8%
1991 RG final
Courier - 7.9%
Agassi - 3.6%
1993 RG final
Bruguera - 1.34%
Courier - (-1.00%)
That's right, Courier had a negative AM against Bruguera (though he's not the only player I've had negative numbers for).
That basically means he the cost he paid in unforced errors was greater than what he was able to win through aggressive plays.
But Bruguera's AM was not much higher. On clay this should not be that much of a surprise.
Last edited by krosero : 07-30-2013 at 10:45 AM.
|01-07-2013, 08:01 PM||#49|
Hall Of Fame
Join Date: Oct 2011
Doesn't look like much of a competition.
|01-08-2013, 06:52 AM||#50|
Join Date: Jul 2008
Also, Brignacca provides the average AM's for the 2005 Grand Slams in the paper you linked in the OP. For men, he has them as follows.
Would it be fair or proper to add or subtract a surface factor when comparing performances in matches played on different surfaces? For example, Rafa's AM in the 2008 RG final was 34.7%, but that might equate to a 53.0% performance at Wimbledon if we added the difference between the French and Wimbledon AM averages.
|01-08-2013, 09:05 AM||#51|
Join Date: Dec 2005
|01-08-2013, 06:47 PM||#52|
Join Date: Dec 2006
One caveat, though, is that surfaces change over time. The clay at RG in the '90s may well have been slower than it was in '05 when Brignacca got his numbers.
And of course technology changes over time, esp. racquets and strings.
So yeah Rafa's top RG performance should probably be thought of as GOAT-level for clay; so if you imagine the equivalent quality on grass, I guess Nadal's number would be somewhere over 50%.
I wouldn't try to quantify it more precisely than that. Too many variables.
I want to start comparing these AM's that I've posted in distinct pairs -- like comparing two USO finals in consecutive years between the same players. That controls the context and reduces variability in factors like surface, which is definitely a major factor to consider when using AM's.
|01-08-2013, 06:53 PM||#53|
Join Date: Dec 2006
Here's a quick example to start.
2000 USO final
Safin - 32.3%
Sampras - 21.7%
2001 USO final
Hewitt - 27.8%
Sampras - 14.2%
Nothing too surprising here. Most people who have seen these matches would say, I think, that Safin's level of play was higher than Hewitt's. Not that Hewitt's play was low -- and these figures give a sense of how high it was -- but still, Safin's performance is regularly named as one of the best of the Open Era.
And when you watch the matches you can see plainly that Sampras runs out of gas in '01. Again these figures give some statistical idea of how far his quality dropped.
Nothing too controversial here, just an opening example of how to use AM's to study matches within a controlled context.
|01-08-2013, 07:26 PM||#54|
Join Date: Dec 2006
1987 USO final
Lendl - 18.75
Wilander - 12.4%
1988 USO final
Wilander - 13.8%
Lendl - 12.2%
Between these two matches, I had always regarded the 1988 final as superior quality. That's because there was somewhat more net play; in '87 the rallies seemed to be longer. It was like watching paint dry, is the way Tony Trabert put it in the booth.
But a few years ago I rewatched the matches, counting winners and service percentages, all the stuff I usually get in my own stats. When I finished watching I actually felt like the '87 final was better played. And the '87 final has higher AM's, as I found out later when I calculated them.
It's true that Lendl was hitting powerful winners all over the place in '88. But he was also making a lot of unforced errors. And his serve really failed him: he made only 42% of first serves -- just 24% in the final set. When he got his serves into the box he made some booming aces; and when he landed his groundstrokes his winners were awesome. That gives the impression of a more exciting match -- which it was. I still would call the '88 final the more exciting one. But I doubt, now, that it had the higher quality.
Lendl was more clutch in '87, especially with his serve. His service percentage never deserted him the way it did in '88; and he actually made some big first serves on a few huge points in the '87 match.
In '87, when everyone was watching the paint dry, there was a stage deep in the long third set when it seemed that neither player could get any kind of advantage. Someone at Tennis Magazine wrote that the two players were fighting over every point, and every game, like two dogs over a bone. And the rallies were often very long, featuring endless backhand exchanges. A lot of people would find that boring, and in some ways it was.
But I remember an exchange in the booth. I think Trabert said that Wilander, despite pulling ahead occasionally, just couldn't consolidate, could not put Lendl away. Newk replied immediately that Lendl couldn't put HIM away either.
And that's the thing: Lendl could not always hit through Wilander. He had the weaponry to do it sometimes, but when Wilander started doing his sprints, Lendl could get into real trouble trying to put Mats away. In other words, he could easily start missing, if he pulled the trigger too soon.
So I think Lendl played well within himself in '87. He couldn't put Mats away so he didn't try to do so prematurely. He was patient enough -- and just barely aggressive enough. He struck the right balance. His patience did make the rallies longer, and could put some people to sleep. But in the end he played his opponent the way he needed to do.
I think the AM's reflect all that. On the other hand, I don't think the AM's reflect too well some of the improvements in Wilander's game in '88. Wilander came to net a lot more in '88; and his service percentage was much higher. His slice, as many people have noted, was working to perfection in '88; it kept Lendl from teeing off, and put him slightly off balance. That had something to do with Lendl making unforced errors; it wasn't JUST a drop in Lendl's quality that was responsible for all his errors.
The AM's do show an improvement by Wilander in '88, though maybe not as much as you would expect to see.
Last edited by krosero : 01-08-2013 at 07:35 PM.
|01-08-2013, 08:38 PM||#55|
Hall Of Fame
Join Date: Apr 2005
Matchups like Lendl-Wilander imo show, how difficult it is, to determine level of play and to define unforced or forced errors. Both played more on long term strategy, a sort of position war, Lendl a bit too defensive for my gusto, Wilander 1988 more willing to attack on certain points. A match is not decided by the sum of games or points, but by winning the decisive quality points, there are big points and minor significant points. And still the point on the same scoring situation could be more important in different situations. For example: A 40-15 point for a server has different worth than in a 15-40 situation, if the returner is leading.
To the unforced error question. In such a match Lendl- Wilander you could bring up the hyothesis - i now make a too radical argument to get the point over - that they played no unforced errors at all. The same shank is a different error, when hit after one excange or hit after an excange of 30 strokes and more, when the player is near to collapse. So in a way, in such a long match with many extremely long exhausting rallies, many more " easy" appearing errors are "forced" (by nature, exhaustion, mental fatigue and other factors) than in other matches, where a shank is a shank, by lack of concentration, bad positioning, bad stroke production or other pure technical or form factors.
|01-08-2013, 10:03 PM||#56|
Join Date: Dec 2008
|01-09-2013, 06:53 AM||#57|
Join Date: Aug 2009
Location: Gliwice, Poland
First of all I would like to say that 'aggresive margin" method of calculating players performance is very interesting, although the results are surface - dependent.
Let's assume that all matches are played on the same surface. Does "aggresive margin" method allow us to judge player's performance objectively? Well, it comes close to that, however it has got some drawbacks.
- it assumes that all point are equally important, which is not always the case in tennis; sometimes the player who wins less points than his/her opponent, wins the match,
- the value of 'aggresive margin" for a player in one particular match, depends not only upon the quality of performance [of this player], but also upon the quality of opponents' play,
- is there an objective method to tell unforced errors from forced errors?,
- points ending in unforced errors may be of very different quality
|01-09-2013, 12:59 PM||#58|
Join Date: Dec 2006
That said, the player who wins the most points, the vast majority of the time, is the player who wins the match. What I like about the AM method is that it always tells you who won the most points; which is the reason that the player with the higher AM almost always wins the match. There is a stronger correlation with the AM than with other common methods which often give the wrong impression about who won the match or about what the margin of victory was (methods like winner/ue differentials and ratios).
When you do come across a match in which the loser has the higher AM, you know automatically that he must have played the important points more poorly. You won't know, of course, which points those were; totals can never point to specific moments. But you will know that the loser's quality of play on important points was lower than the victor's: and that's something you would want to be reflected in any stat, even if the details are something you can only look up by taking a close look at the match.
I have some matches like this. Safin trailed Federer 194-201 in total points at the 2005 AO despite winning the match; so his AM trails Federer's, 19.0% vs 20.8%. The year before there was a similar situation at the 2004 AO, between Safin and Agassi: Safin won fewer points in total, and therefore had the lower AM, but won the match.
Another example is Nadal d. Federer in Rome (the important points lost by Federer in that match can be very simply identified, in that case: he made two UE's on the two match points that he held). Two more examples are Federer d. Agassi at the 2004 USO, and Agassi d. Medvedev in the 1999 RG final, etc.
All of this is to say that the AM, because it tracks the total points won, has a built-in way of telling you who produced the higher quality of play consistently from point to point, over the course of the match (something we would want to know, and which is a strength in any player); and who played better on the important points (something we would also want to know, if it's not the same person who won the most points).
I do think that tennis stats are growing increasingly sophisticated and can focus in on incredibly detailed moments: like telling you how far back Roddick is standing when he returns serve on break points.
Those details are unquestionably important. Tennis writers have always focused on them; it's more difficult to measure them broadly with objective stats, but I think tennis stats are getting there.
As for the argument about not all unforced errors being the same, I can only agree wholeheartedly.
Two strokes may both be wide forehands, and may be executed the same way from a superficial standpoint; but one occurs on the second shot of the exchange, under little pressure, while the other occurs at the end of a wild 30-stroke rally. Unquestionably there's a huge difference.
All that has an impact on the AM's, though I think you can identify the impact and account for it.
Let's take Wilander and Lendl as an example. There you have two great defenders engaged in long rallies. Their AM's in the 1987-88 USO finals were relatively low, because two defenders facing each other will find it hard to hit through each other and pull off winners.
Next year, Wilander loses to Sampras in five sets, and Mats has an AM of 29.8%. Now, was his quality of play really higher than the previous year when he beat Lendl with an AM of 13.8%? Not a chance.
The reason his AM is so high against Sampras is that Sampras came into net relentlessly, forcing to Wilander to make errors or to hit winners: so Mats just didn't have that many chances to make unforced errors. That's the general rule about errors: if you make an error while you're opponent is at the net, your error is typically judged as forced.
The unforced errors that Wilander did make in the Sampras match, when he had a chance to make them, did not come at the end of grueling 50-shot rallies; they were more genuinely "unforced errors" in the ideal sense of that term: unnecessary, sloppy errors.
Knowing all this, you know not to jump to the conclusion that Wilander's level of play in the '89 match was superior to what he did in '88.
I think AM comparisons work best when you can judge AM's that took place on similar surfaces, between opponents of similar style. If there is some radical difference in how the unforced errors occurred, in two matches, then the AM's cannot be used in a straightforward manner, if at all.
Terrific comments, Urban. I always enjoy your comments about match dynamics.
|01-09-2013, 01:43 PM||#59|
Join Date: Dec 2006
Federer - 38.4%
Djokovic - 32.9%
Federer - 30.6%
Murray - 25.7%
2012 London Olympics
Murray - 34.2%
Djokovic - 27.6%
Murray - 29.7%
Federer - 12.1%
Now here is a group of matches without any of the problems discussed above. The venue and surface did not change; the matches took place just one month apart; and the style of play was basically the same, from all three players.
There was a large dropoff in the quality of Federer's play, between the Wimbledon final and the Olympic final. Murray's quality of play was very similar in both matches; and in the Olympic final Murray's level was arguably just as high as what Federer had achieved in the Wimbledon final.
Djokovic experienced a bit of a dropoff at the Olympics -- but not a large one -- if you compare his losses to Federer and to Murray.
Murray, unlike Federer and Djokovic, raised his level of play, going from Wimbledon to the Olympics. And Murray's level of play when he defeated Djokovic was extremely high, almost the highest in the whole group of matches.
The highest performance of all was nevertheless Federer's, in his Wimbledon semifinal over Djokovic.
The roof was closed throughout that match, which is the one change in conditions that I can think of, among these matches. (It was also closed for the last part of the Wimbledon final.) Indoor conditions tend to help Federer; and though I cannot prove it statistically, I would expect AM's to be higher indoors. AM's are generally higher in faster conditions because it's easier to hit winners and to force your opponent into errors.
Last edited by krosero : 01-09-2013 at 01:49 PM.
|01-09-2013, 02:39 PM||#60|
Join Date: Aug 2009
Location: Gliwice, Poland
I would say that AM is a good measure of players' performance because it is relatively simple and it tells you a lot about what happened on a tennis court during a particular match, however this is not an absolute (objective) measure of the match quality (well, perhaps it is, but not a perfect one).
Let's assume that two players played a tennis match. After the match, they calculated their AM's (30% and 20% respectively).
On the second day the players played the second match. The first player performed better than on the first day, so did the second competitor. After the match they calculated their AM's which happened to be exactly the same as in the first match.
Finally, on the third day both players performed better than ever, however their AM's were still the same as previously.
Overall AM's are not always a sensitive measure of player's performance.
On the other hand one could argue that this examples are purely theoretical, without any significant relevance to real tennis matches.