I have never seen Hawk-Eye technology to be used on clay tournaments. French Open is running at the moment and it is not being used there.

  • What are the reasons for not using this technology on clay?
  • Do tennis federations have some rules against it?
  • 2
    The funny/ironic thing about clay tournaments not using Hawkeye, and claiming that it is not necessary because of the mark left by the ball, is that there have been some rather long and drawn out disputes with the chair umpires by players not agreeing with them about their interpretation of what they see by the mark left on the court. While in general, it's true that the mark is "good enough" in a large majority of close calls, there are still some times where the players and chair umpire don't agree - and in those cases, the players are at the mercy of the chair umpires decision.
    – jamauss
    Jun 2 '13 at 19:42
  • I see that link to the blog post in the previous comment is now dead. Here is an Internet Archive version.
    – Martin
    Mar 17 '19 at 0:43

You are right that the French Open is the only Grand Slam tournament without Hawkeye,

The reason is that Clay, unlike grass and hardcourts, leaves a mark that players and umpires can check and verify if the ball was in or out.

You can argue that some mistakes can be made but that's quite rare, A hawkeye system is very expensive and the cost/benefit ratio doesn't pays.

Gilbert Ysern, the director general of the French Open and a former umpire, address to this:

“I don't think we need it,” he said in an interview in his office.

“There are ball marks on clay,” Ysern said with a genial smile, “and our chair umpires are used to checking the marks when needed, and, so why would we need Hawk-Eye?”

And the disputes? “It happens very, very rarely that the officials can't find the mark,” he said.


  • 5
    Actually Roland-Garros, the French Open, is equiped with the Hawk-Eye system. They only use it for tv broadcasting. Nov 20 '14 at 16:41

I strongly suspect that the manufacturers of Hawkeye and similar ball tracking systems would actually prefer not to have a hard 'ground truth' to compare to being beamed live to millions of viewers. These systems are not as accurate as the TV graphics imply and there use as part of the umpiring process is not all to do with accuracy. It is as much about having a non-human, dispassionate system have the final say when the humans can't agree as arguing with a machine is futile.

The manufacturers of Hawkeye claim a mean accuracy of 3.6mm, although this figure, or at least its interpretation has been called into question. Basically, since this is an average over some range of shots, it is likely that the actual error in certain circumstances is significantly higher (as detailed in the second reference). Errors approaching 10mm could easily turn the correct result, as observed by the skid mark on clay ground truth, into an incorrect Hawkeye call. It would be terrible publicity to have a top player angrily pointing to the clear evidence on the court that differs from the Hawkeye prediction.

  • 1
    This doesn't answer the question.
    – wax eagle
    Jun 6 '13 at 17:00
  • How so? You might not agree with the answer, or think it's a good one, but it certainly answers the question. Jun 6 '13 at 23:57
  • 1
    Link in the post is not working at the moment. Did you mean the paper by Collins and Evans, which is also among references in Wikipedia article on Hawk Eye? Links: Google, Google Scholar.
    – Martin
    Jun 7 '15 at 14:21

Clay courts leave a visible mark which shows where the ball lands. This is the reason why the staff at Roland Garros clear the court often during a match so there wont be overlap of marks(or mistake of the actual mark), which can cause confusion.

If a ball is questionable, then the referee will come down and check the mark on the court and make his decision about whether it was in or out .


Balls can skid much longer distances on clay. On hard courts only the ball measurably changes (deforms) on impact. On clay both the ball and the court are changing simultaneously as a layer of dirt is shifted around. These factors make Hawk-Eye's job more challenging on clay and it would be logical to conclude that Hawk-Eye's margin of error increases on clay.


Hawk Eye is in general more accurate than the human eye but that doesn't mean it's 100% perfect. It will always remain an approximation of the "ground truth". With clay courts we have the unique ability to see the actual physical mark. This hard, physical evidence should be always preferred to approximation, no matter how accurate.

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