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Sport and Exercise Psychology Services

How do we make use of the 'Unforced Error' statistic

Anyone who watches professional tennis can't help but notice the amount of statistics that are kept on each match. First and second serve percentage; first and second serve points won; break points earned; break points won; total points won and so on. Similar statistics are kept in other sports too. Examples are greens in regulation or footballers' distance run. Most of these statistics are useful to the spectator, giving them a deeper understanding of key performance indicators in a sporting contest. There are, however, several statistics that are displayed during a tennis match that are at best underutilised and at worst give a misleading impression of a player's performance.  One of these statistics is the Unforced Error.

What is an Unforced Error?

This statistic is shown to the spectator in Tennis matches and is called the Unforced Error. An unforced error occurs when a shot is missed by a player (the player hits the ball out or in the net). This error is not the result of any significant pressure placed upon the player by his opponent. It is an error that cannot be attributed to any factor other than poor judgement and execution by the player committing the error. It is judged to be a mistake.  The unforced error sits in contrast to the Forced Error which is an error caused by an opponent's good play.  Judging what is a forced or an unforced error is subjective but in 90% of errors the difference between the two is clear.  The problem with the unforced error statistic is not that it is judged subjectively but that it is  too general, can be misleading and does not give an accurate picture of what happened during a match.

 

A Misunderstood Statistic

 The unforced error statistic is built up over a match and used to gauge the consistency, or inconsistency, of a player. The term 'unforced' suggests that the error was made without force or pressure.  It would be  far more useful to know whether the source of the error was technical, tactical, physical or mental. By breaking down the reasons for the error, both spectator and player  will have a significantly more accurate view of what the player needs to work on to improve and develop their game. 

Break the Unforced Error Statistic Down?

 By breaking the unforced error category into statistics, much needed evidence of the extent to which competitive matches are influenced by each of the four areas of skill development (mentioned above) would be provided. In addition, spectators would gain a statistical knowledge of the competitive benefit of being 'technically sound', 'tactically aware', 'physically fit' or, crucially, 'mentally tough'. Of course, no system of record keeping is perfect. Each error has to be classified by someone in one of these categories, making it somewhat subjective. However, the classification of an error into 'forced' or 'unforced' is never challenged so why not expand the number of categories in order to develop this potentially useful statistic.

We should be producing tennis statistics that actually provide enlightenment for the spectator and player alike?

A case in point

 If we look at a recent example - the shock semi-final defeat of Serena Williams by Roberta Vinci at the 2015 US Open Tennis Tournament. The match statistics recorded that Serena Williams recorded 40 'unforced errors' while Roberta Vinci recorded only 20 'unforced errors'. However Serena hit 50 winners compared to Vinci's 19. This would suggest that Serena should have won. Now, let's imagine if 5 of those unforced errors were attributed to physical fitness problems (slow recovery from a long point), 5 to tactical problems (a failure to adopt the strongest court position), 12 to technical problems (overuse of the arm rather than full body) and 18 to mental problems (e.g. Concentration, failure to cope with nerves in the situation). How much more informed would you feel now - as spectator, player or coach - about the match? 

Without doubt, the number of 'unforced error' points in any tennis match seriously impacts the outcome and we can conclude that Serena probably missed a lot more shots than we would normally expect her to. However, imagine how much more informed the viewers, and Serena herself, would be if these 40 errors had been broken down into each of the four categories above. From a mental training perspective, I would suggest that these statistics would help to promote the significant benefits players could gain by committing more time to the mental side of their game.

 

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