Tennis line judges are more likely to make mistakes when calling balls "out" rather than "in", say...

Tennis line judges are more likely to make mistakes when calling balls "out" rather than "in", say researchers.

This was [due] to a time lag of a few hundred milliseconds between an image hitting the retina and the viewer processing it, the team said.

This bias, revealed in Current Biology, could enable players to exploit the "challenge" system, they suggested.

To test this, video clips of 4,000 random Wimbledon points were examined and any incorrect calls logged.

If this "bias" did not exist scientists would have expected the number of balls wrongly called "out" to equal the number wrongly judged "in".

In fact, of 83 calls, 70 of the errors were wrong "out" calls.

BBC News - From watching just the grand slam events, the majority of overturned line calls go from "out" to "in". Of course, this could be because players mostly challenge "out" calls. Ah, Type I and II errors, how you plague us.

over 3 years ago Sky Kalkman 2 comments 0 recs |

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Hmm... interesting.

Although a false positive could be viewed as a false negative from another viewpoint in sports.

Clutch: A measurement of how much better or worse a player does in high leverage situations than he would have done in a context neutral environment. http://www.fangraphs.com/blogs/index.php/glossary/

by bdalebs on Nov 1, 2008 2:27 PM EDT reply actions

My Type I/II comment was directed at player challenges.

They could err by challenging a call that was actually correct or they could err by not challenging a call that was actually wrong.

During grand slam coverage I’ve seen statistics that judge players (and genders as a whole!) by the percentage of challenges that they get right. But you really need to also know how often each player is failing to challenge calls that would have gone his/her way. It’s like the reason fielding percentage is a crappy stat. Sure, making errors isn’t a good thing, but if you’re a statue and never get to any balls, you’ll never make any errors.

Beyond the Boxscore // Calling BJ Upton lazy is lazy.

by Sky Kalkman on Nov 1, 2008 3:10 PM EDT up reply actions