Court speed ratings by Tennis Insight

[Benhur]

Court speeds ratings by Tennisinsight.com

At this site they give a rating for each tournament, which they claim to infer from match results.

Quote:
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“Generally, matches on faster courts have fewer points, more games and more tie breakers. “Court speed” is thus inferred from completed match results and whilst not a true measure of how quickly the court is playing it does provide some useful insight on this."
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Below are their ratings for the main tournaments on the three surfaces over the last 12 months. Whatever their method consists of, it shows the grass tournaments considerably faster than the others (except Cincinnati). But then it does a poor job differenciating between hard and clay. Cincinnati is shown as the fastest hard court tournament by far, followed by Miami. The USO is shown as barely faster than Indian Wells and actually slower than the French Open (!?????) and Montreal is rated slower than all the clay tournaments. Clearly this method needs improvement.

By comparison, the ratings inferred merely from hold percentages (or break percentages) as calculated by Bud and NF before him, show a much finer gradual differenciation without any big surprises from what is generally perceived when it comes to the relative speeds between surfaces (except for the perception of Wimbledon’s slowness). It shows a gradual increase in speeds in a sequence that goes Monte Carlo, Rome, French Open, Australian Open, USO, and then grass. I suspect the people at tennis insight need to reconsider their method. There is no way the USO plays like the clay tournaments. And there is no way Indian Wells is slower than Monte Carlo. For whatever is worth, these are some of the ratings at tennis insight:

GRASS:

Wimbledon 2010
Rated: 0.86
Percentile vs all courts: 26.58%
Percentile vs Grass: 39.09%
Note that the lower the percentile, the faster the court is rated.

Queen’s 2010
Rated: 0.85
Percentile vs all courts: 26.89%
Percentile vs Grass: 42.73%
Note that the lower the percentile, the faster the court is rated.

Halle 2010
Rated: 0.84
Percentile vs all courts: 27.35%
Percentile vs Grass: 45.45%
Note that the lower the percentile, the faster the court is rated.

HARD COURTS

Cincinnati 2009
Rated: 0.86
Percentile vs all courts: 26.55%
Percentile vs Hard Court: 21.86%
Note that the lower the percentile, the faster the court is rated.

Miami 2010
Rated: 0.78
Percentile vs all courts: 31.46%
Percentile vs Hard Court: 25.56%
Note that the lower the percentile, the faster the court is rated.

US Open 2009
Rated: 0.75
Percentile vs all courts: 34.71%
Percentile vs Hard Court: 30.64%
Note that the lower the percentile, the faster the court is rated.

Australian Open 2010
Rated: 0.74
Percentile vs all courts: 36.19%
Percentile vs Hard Court: 32.19%
Note that the lower the percentile, the faster the court is rated.

Indian Wells 2010
Rated: 0.74
Percentile vs all courts: 36.92%
Percentile vs Hard Court: 32.96%
Note that the lower the percentile, the faster the court is rated.

Montreal 2010
Rated: 0.70
Percentile vs all courts: 45.83%
Percentile vs Hard Court: 41.39%
Note that the lower the percentile, the faster the court is rated.

CLAY

French Open 2010
Rated: 0.76
Percentile vs all courts: 33.33%
Percentile vs Clay: 31.31%
Note that the lower the percentile, the faster the court is rated.

Rome 2010
Rated: 0.75
Percentile vs all courts: 35.70%
Percentile vs Clay: 34.31%
Note that the lower the percentile, the faster the court is rated.

Madrid 2010
Rated: 0.75
Percentile vs all courts: 34.28%
Percentile vs Clay: 32.55%
Note that the lower the percentile, the faster the court is rated.

Monte Carlo 2010
Rated: 0.72
Percentile vs all courts: 41.41%
Percentile vs Clay: 41.02%
Note that the lower the percentile, the faster the court is rated.

 

[ballboy48]

How could USO be slower than FO? This is useless.

 

[Benhur]

How could USO be slower than FO? This is useless.

I know. I told them a while back. Other than the grass tournaments showing up as faster, and Cincinnati a relatively fast hard court, the other stuff makes no sense. They need to refine whatever method they are using.

 

[drakulie]

hahahahaha. They need to go back to the drawing board.

 

[AznHylite]

Wow these guys are idiots lol.

 

[Bud]

Court speeds ratings by Tennisinsight.com

At this site they give a rating for each tournament, which they claim to infer from match results.

The ITF has a scientific method for rating all surfaces and they've rated the current Wimbledon surface (see below). I can't find the info anywhere on-line, however.

http://www.itftennis.com/technical/equipment/itfguidetotestmethods/courtpace.asp

http://www.itftennis.com/technical/research/lab/courts/


Surface pace testing on Centre Court at Wimbledon

Figure 2. Test apparatus for measuring court pace.​

- - - - - - - - - -


Perhaps, I'll email the ITF and ask them what their rating is for various courts on tour. Their rating for the AO is on the AO web page.

 

[Bud]

I know. I told them a while back. Other than the grass tournaments showing up as faster, and Cincinnati a relatively fast hard court, the other stuff makes no sense. They need to refine whatever method they are using.

Did they consider the ball type?

 

[veroniquem]

Maybe Rafa hasn't won the USO yet because it's too slow, lol.

 

[Talker]

Here's another method used.

http://www.tennisform.com/default.asp?&tournament=none&action=GPS&direction=asc&sort=GPS

 

[vortex1]

I knew they sped up clay!:twisted:

 

[Bud]

IMO, the ITF could probably use Hawkeye and a high-end ball machine to determine surface speed. They could then run tests using various amounts of topspin to test both the COF and the COR of each surface... taking the average of 10 readings at various point on the court.

With this method, they'd obtain both the numerical data and a visual to compare surfaces... and they could also use the same balls the tournament uses in competition.

 

[GameSetMatch]

Just goes to show how fallible 'scientific' measurements are.

 

[Bud]

Just goes to show how fallible 'scientific' measurements are.

Explain, not following you

 

[aceX]

Monte Carlo faster than Montreal?

This is brilliant.

 

[aceX]

If this stuff is correct, then the ball specifications significantly contribute to playing speed.

 

[Macro80]

That ridiculous, it is well known here that Queens is significantly faster than Wimbledon these days. They did not make the switch to 100% Rye and 8mm grass like Wimbledon did.

 

[aceX]

Well ****, they have data and you have none, so...

 

[Macro80]

Well that absolutely depends on the methods use to acquire said data and the actual validity of that data itself.

The OP suggests this is "inferred" by results so i would be suspicious as to whether this data wold stand up to the rigors of the scientific method.

Accepting data blindly is just ignorance.

 

[Benhur]

Did they consider the ball type?

No.Their rating does not involve any testing. They derive it from statistical data of matches. The only thing they explain about their method is the bit I quoted in my opening post.
My guess is they are just looking at total points vs total games, tiebreaks etc. Whatever they are doing, they should drop it as the results clearly make no sense.

Main problem is that court speed is not a defined physical quantity. It is a perceived characteristic that depends mostly on the amount of friction and the amount of vertical restitution. The term speed is misleading, as a very low restitution such as that offered by a court with abnormally thick and long grass that plainly would absorb most of the balls energy would mean a "fast" court. But still it would be good if these tests were somehow standardized and applied to the main surfaces (using, of course, the exact type of ball actually used in each surface).

If this were done, it would then be possible to find out more precisely which statistical data or combination thereof shows the highest sensitivity to variations in measured court speed.

Given that the amount and quality of available statistical match data in tennis is pretty dismal compared with other sports, like baseball, this would take some resources. But the ATP now seems to be keeping more detailed statistics, and it should be possible.

Until this is done, I remain convinced that the most logical place to look into is the relative success of serving vs returning over large samples of data (the entire field in each tournament). Holding (or breaking) percentages are so far the easiest data to examine in this regard. It would probably be even better to examine the ratio of total points won by servers vs returners, as well as other data researchers may deem relevant. It is indisputable that, other things being equal, an increase in court "pace" increases the initial advantage of the server, and this should show up over sufficiently large amounts of data. And in fact it does show up, as already demonstrated by breaking percentage calculations. They do agree pretty well with the *perceived* speed of different courts. It remains for this to be validated with actual physical tests, and then devising additional data analysis that detects the measured surface variations even better than the holding/breaking percentages already do.

In the meantime, court speed will remain a purely impressionistic and anecdotal gossip item. Johny said the courts were playing fast yesterday. Joe said they looked slow today in a certain match. Mike says that Paul's slice was clearly skidding in some shots. Jeremy makes the sharp observation that Rafa's forehand was bouncing too high, and so on.

In any case, yes, those ratings a posted cannot be taken seriously.

 

[abmk]

benhur

this insight into the court speeds doesn't really make much sense

 

[elroyjet]

how can you derive court speed from just tennis stats? there's so many factors involved.

i recall in mcenroe's book (patrick's) that he talks about court speed. the itf says the fastest a court can be is a "50" i think. and that depends on the court surface mixture.

 

[Benhur]

how can you derive court speed from just tennis stats? there's so many factors involved.

i recall in mcenroe's book (patrick's) that he talks about court speed. the itf says the fastest a court can be is a "50" i think. and that depends on the court surface mixture.

You can't measure it with any stats. But with sufficiently large amounts of data you can detect fairly stable differences that can only be accounted for by the court, other random factors tending to cancel out over large samples. Of course such analysis would have to be validated with actual measurements or at least perceptions. The ratings by Tennisinsight are plainly the result of a flawed or blunt analysis because they are in terrible disagreement with common perception. It does not mean the general approach is invalid. It means they are measuring data with poor correlation to court speed.

Imagine for a moment that the distance between bases were slightly different from one baseball field to another. Or imagine that one league used a slightly smaller strike zone than another. A physical difference like that would obviously have to have an effect in a number of stats over the course of a sufficiently large number of games. So the general approach is sound. But definitely, TennisInsight is not being very insightful at all in the way they go about it.

 

[Benhur]

A common flaw in those who deny a relation between court speed and the advantage of the server is that they tend to limit that advantage to the serve itself (the shot), as if the advantage disappeared when the serve is returned. This is clearly not so. The advantage of the server often continues two or three or more points beyond the serve itself. It lingers because a number of those returns are inadequate to bring the point to neutral –they land short, etc.

So on a faster court, the server would get even more of those inadequate returns. And then his ability to hit more effective shots off those returns will also increase. An aggressive shot off a short return will be more effective on a faster court, and so on. In other words, the server’s ability to keep the upper hand increases throughout if the court speed increases.

To me, denying that a faster court helps the server and that a slower court helps the returner, is exactly the same as denying that a larger strike zone wold help the pitcher, and a smaller one wold help the batter. Or denying that these effects will be reflected in any stats.

Since the relation is obvious, it follows that the best place to look would be stats that reflect the relative performance of servers vs returners over large amounts of data where the only constant difference is the surface.

 

[AM95]

fail thread

 

[Murrayfan31]

Court speeds are way off. Grass should be only slightly faster than clay.

 

[sureshs]

French Open appears faster than US Open because of Nadal's game.

 

[srinrajesh]

I wud think with so much technology nowadays they wud find a better way to rate the court speed..

How about using the average Top 200 / 500 service speeds recorded on that court along with Top 200 / 500 groundies. This average of some of the top serve and groundies should compensate absence of any hard hitter in that particular tournament. Another indicator would be the total number of winners on serve and Groundstrokes.

Do we have stats of these speeds and these winners so that we can informally rate the courts?

 

[rk_sports]

I was really excited to see which courts are faster.. until I saw that they got clay faster than hard court .. unless they got a completely different yardstick, its hard to take any of the observations seriously

 

[Bud]

I wud think with so much technology nowadays they wud find a better way to rate the court speed..

How about using the average Top 200 / 500 service speeds recorded on that court along with Top 200 / 500 groundies. This average of some of the top serve and groundies should compensate absence of any hard hitter in that particular tournament. Another indicator would be the total number of winners on serve and Groundstrokes.

Do we have stats of these speeds and these winners so that we can informally rate the courts?

Did you read post #6? Post #11?

 

[Li Ching Yuen]

I believe these ratings.

You people need to consider the balls they use for the US Open which are I believe different from the other grand slams. That plays an important role.

 

[aceX]

Yeah I think people under-estimate the importance of the balls.

 

[intrepidish]

Andy Murray discussing the US OPEN:

http://www.live-tennis.com/category/...-201009040007/


Murray said, ”It's quite clear the balls are a lot faster, a little bit harder to control the balls. Guys are serving harder. But I think the court itself I think grass is definitely still quicker than here. I just think because of the warm weather and obviously the balls being they seem very light in comparison to the Slazengers, which are pretty heavy.

 

[pmerk34]

How could USO be slower than FO? This is useless.

Good grief the French Open this year was like mud it was so darn slow. It was ridiculous.

 

[pmerk34]

I believe these ratings.

You people need to consider the balls they use for the US Open which are I believe different from the other grand slams. That plays an important role.

They use Wilson US Open balls which I ALWAYS break open when playing my brother. That way I can at least ope a few aces and service winners. IF we use Penns I'm dead meat.