There are 26 different sports being played at the 2012 Olympics. Some clearly have a greater link with sports vision than others, but few would have a greater reliance on vision than archery. Or so you would think.
When aiming in archery, it’s better to keep both eyes open as this helps balance. It’s harder to balance on one leg, for instance, if you’ve got one eye closed rather than both open. However, this does present a problem: something must be double.
If you point your finger at a distant object and concentrate on that object, you’ll see two fingers, the one on the left being the one that’s aligned with the right eye. And if you focus on your finger, you’ll see two objects, and this time it’s the one on the right that’s aligned with the right eye.
The other problem is that if you focus on your finger, the object will be slightly out of focus, and vice versa. In archery, the “finger” is a sight on the front of the bow. It seems to promote accuracy by focusing on the target, and having a slightly out of focus bow sight. You also need to make sure that it’s the left hand sight that you’re aligning, assuming that you’re using the bow right-handed.
I said that you’d think that excellent vision would be essential for any level of archery, but in fact some partially sighted or even blind archers can be remarkably accurate. How do they achieve this?
Well, they have two aids. One is a foot locator, which is a wooden frame, and against which they place their feet. It is built to the archer’s stance, which ensures that their feet are in exactly the same position each time. The other is a tactile sight, which consists of a fully-adjustable spring-loaded bar which touches some part of the archer’s hand when the bow is fully drawn. They also have a “spotter” who tells the archer the result of the shot, and helps with adjustments of the tactile sight.
This makes me wonder how care fully sighted archers take to ensure that their body position is exactly the same each time. At an elite level, a side-on video camera could relay picture onto a screen, then you simply subtract one image from the previous one to see if there’s been any change in position. I bet it would be a pretty good guide to the accuracy of the shooting.
Visually impaired archery is not currently an Olympic sport, but it is hoped that it will be by the 2016 Games.
David Donner
Thursday, 28 April 2011
Tuesday, 29 March 2011
Training To Win!
A coach was recently telling me how his Colts side prepared for a big match. Both sides were unbeaten all season, but the other team were quite strong favourites.
A couple of days before the match his colleagues advised him that some light training would be best, but he insisted on a full contact session. His team went on to win the match 10 -9. The opposition had a long period of play just a few metres from the line, but time and time again the tackles were made to prevent them crossing for a try.
Obviously a balance needs to be struck. You need to give the players a chance to recover from a previous match, and you don’t want them exhausted because they’ve over-trained. But as a general principle, practice should be in some respects at least as difficult, if not harder, than playing a match.
So if you’re wondering why England failed to win the Grand Slam in Dublin, and were completely outplayed and outfought by Ireland, then maybe you need to know just one thing: England had only light training all week.
David Donner
A couple of days before the match his colleagues advised him that some light training would be best, but he insisted on a full contact session. His team went on to win the match 10 -9. The opposition had a long period of play just a few metres from the line, but time and time again the tackles were made to prevent them crossing for a try.
Obviously a balance needs to be struck. You need to give the players a chance to recover from a previous match, and you don’t want them exhausted because they’ve over-trained. But as a general principle, practice should be in some respects at least as difficult, if not harder, than playing a match.
So if you’re wondering why England failed to win the Grand Slam in Dublin, and were completely outplayed and outfought by Ireland, then maybe you need to know just one thing: England had only light training all week.
David Donner
Thursday, 3 March 2011
Rugby Passing 2
Of course backs are also perfectly capable of dropping the ball. One of the most common causes is simply taking their eyes of the ball, being distracted by the opponent advancing towards them, or looking at the inviting try line ahead, for instance. This is particularly likely to happen if your passing drills are unopposed.
It could be that the weather is particularly bad on the day of the match and the ball is slippery. But why not practice this by making the ball deliberately wet or greasy? As well as preparing the players for quite a likely eventuality, it would also make them watch the ball into the hands more carefully.
There is another category of errors which comes from when the ball shouldn’t have been passed at all, because there was no one in position to take it. One of the things that set the top players apart is their decision making. They take the opportunities that come their way, but they don’t make rash decisions if the opportunity isn’t there.
A simple variation to touch rugby could introduce the concept of decision making from a young age. The attacking side forfeit the ball if they’re touched in possession of knock on as usual. But they would also have another option. If a player shouts “tackle” before they’re touched, they must stand still, but are allowed to pass the ball when a team-mate becomes available. The coach would decide how many times this “tackle” option would be allowed before the usual rules are back in play.
The key to making good decisions is using ones vision to analyse the situation as much in advance as possible. The players should therefore be told that they should expect that the ball is always going to come to them, and to think about what they’re going to do before the pass to them is made. But they also need to keep monitoring the position of their own and opposition players so they can change their mind at the last moment if necessary.
David Donner
It could be that the weather is particularly bad on the day of the match and the ball is slippery. But why not practice this by making the ball deliberately wet or greasy? As well as preparing the players for quite a likely eventuality, it would also make them watch the ball into the hands more carefully.
There is another category of errors which comes from when the ball shouldn’t have been passed at all, because there was no one in position to take it. One of the things that set the top players apart is their decision making. They take the opportunities that come their way, but they don’t make rash decisions if the opportunity isn’t there.
A simple variation to touch rugby could introduce the concept of decision making from a young age. The attacking side forfeit the ball if they’re touched in possession of knock on as usual. But they would also have another option. If a player shouts “tackle” before they’re touched, they must stand still, but are allowed to pass the ball when a team-mate becomes available. The coach would decide how many times this “tackle” option would be allowed before the usual rules are back in play.
The key to making good decisions is using ones vision to analyse the situation as much in advance as possible. The players should therefore be told that they should expect that the ball is always going to come to them, and to think about what they’re going to do before the pass to them is made. But they also need to keep monitoring the position of their own and opposition players so they can change their mind at the last moment if necessary.
David Donner
Passing In Rugby
The standard of passing in the Six Nations so far this season has been rather variable, from excellent to the frankly ridiculous. Sometimes the guy with the ball is so desperate to keep the ball alive, either to stop it going out of play and conceding a line out, or because having beaten two or three people he’s got carried away, that a totally inappropriate pass is given, which the receiver has no chance of catching, and may even be picked off by the opposition.
Sometimes, however, a perfectly acceptable pass is made, and then dropped. If it’s a forward who’s dropped the ball, there tends to be a collective “If only that had gone to a back” reaction. But how much time is spent on improving the handling skills of forwards?
The process of catching the ball starts long before the hands try to make contact with the ball. The fly half could probably recognise the type of pass (e.g. spin, pop pass or loop pass) from the scrum half well before the ball is actually released. But a forward is less likely to be less able to do this.
So one could start by getting the scrum half to demonstrate some different passes to the forwards who would be told to watch how the scrum half shapes to pass the ball, to watch the ball into the hands, and to pay particular attention to the feel of the ball in the hands when it’s caught. This is then repeated while taking the ball on the run. Some deliberately poor passes – too high or low – can be added as passes won’t always be perfect in a match.
The final stage would be to convert this drill into a more realistic match practice. For instance, three forwards have to score a try past two defenders. The move begins when the scrum half makes one of the previously demonstrated passes to one of the forwards of his choice as they’re running forward. The three then have to use passing and movement to ensure their numerical supremacy counts.
David Donner
Sometimes, however, a perfectly acceptable pass is made, and then dropped. If it’s a forward who’s dropped the ball, there tends to be a collective “If only that had gone to a back” reaction. But how much time is spent on improving the handling skills of forwards?
The process of catching the ball starts long before the hands try to make contact with the ball. The fly half could probably recognise the type of pass (e.g. spin, pop pass or loop pass) from the scrum half well before the ball is actually released. But a forward is less likely to be less able to do this.
So one could start by getting the scrum half to demonstrate some different passes to the forwards who would be told to watch how the scrum half shapes to pass the ball, to watch the ball into the hands, and to pay particular attention to the feel of the ball in the hands when it’s caught. This is then repeated while taking the ball on the run. Some deliberately poor passes – too high or low – can be added as passes won’t always be perfect in a match.
The final stage would be to convert this drill into a more realistic match practice. For instance, three forwards have to score a try past two defenders. The move begins when the scrum half makes one of the previously demonstrated passes to one of the forwards of his choice as they’re running forward. The three then have to use passing and movement to ensure their numerical supremacy counts.
David Donner
Friday, 4 February 2011
Peripheral Illusion
Have a look at this website:
http://richardwiseman.wordpress.com/2011/01/12/wonderful-new-illusion
It’s a wonderful example of the differences between the central and peripheral parts of our vision. The central part is especially sensitive to detail and colour, whilst the periphery is more sensitive to movement and faint light.
The difference reflects the different light-receptor cells that are present in the retina – cones in the centre and rods more peripherally. It’s why in the days of navigating by starlight, sailors were told to look for faint stars out of the corner of their eye.
Most of our waking time is spent using our central vision, such as looking at a computer screen or TV, reading or talking one-to-one. If there’s something peripherally of interest we tend to turn our head to look at it.
In many sporting situations, however, it’s necessary to be able to assimilate a lot of information from the periphery, such as the movement of team mates, even if the main focus is on the opponent directly in front.
This can be learnt, with the right kind of coaching.
David Donner
http://richardwiseman.wordpress.com/2011/01/12/wonderful-new-illusion
It’s a wonderful example of the differences between the central and peripheral parts of our vision. The central part is especially sensitive to detail and colour, whilst the periphery is more sensitive to movement and faint light.
The difference reflects the different light-receptor cells that are present in the retina – cones in the centre and rods more peripherally. It’s why in the days of navigating by starlight, sailors were told to look for faint stars out of the corner of their eye.
Most of our waking time is spent using our central vision, such as looking at a computer screen or TV, reading or talking one-to-one. If there’s something peripherally of interest we tend to turn our head to look at it.
In many sporting situations, however, it’s necessary to be able to assimilate a lot of information from the periphery, such as the movement of team mates, even if the main focus is on the opponent directly in front.
This can be learnt, with the right kind of coaching.
David Donner
Friday, 14 January 2011
The One Eyed Referee
All sports officials are meant to be objective and neutral in their decision making. In theory, therefore, two officials of the same standard should make more or less the same decisions in the same situations. In practice, however, decisions are often made in the context of personal style, the match situation, previous experiences, and (mostly) subconscious biases.
Some sports actually incorporate subjectivity into their laws. In rugby, for instance, the referee is the sole judge of whether or not advantage has been gained. In cricket, the umpire has to decide whether or not short-pitched bowling is unfairly intimidating, taking into account the batsman’s ability. Nevill et al (2002) showed 47 football situations on video to a set of referees. None of them received a unanimous verdict from the refs.
Personal style is undoubtedly a major factor in many decisions. For instance, in rugby, some referees may want to establish their authority early, whilst others may wish to allow the game to flow without being seen to be overly fussy. The referee might be influenced by previous incidents in the game, or even from a previous match between the same opponents. There may also be some benefit given to a side that’s losing heavily.
Trudel, Dionne and Bernard (1999), as well as Gilbert, Trudel & Bloom (1995), in assessing ice hockey penalties, concluded that referees, compared with players and coaches, attached greater importance to the context in which the infraction had occurred. Gilbert et al revealed that both the score and the time remaining in the game influenced decisions about whether or not to award penalties.
Diane Ste-Marie of the University of Ottawa has done a lot of research, especially in gymnastics, into how judgement can be affected by previous experience. She found that if judges were shown a performance on video with an error, they were more likely to see non-existent errors in the second tape. The effect lasted even if the second tape wasn’t seen until a week after the first one, so could affect an athlete performing in several rounds, or even if they’ve been seen in a warm-up. A similar effect has been found in figure skating.
Other assumptions made by officials can be just as erroneous. Damisch et al (2006) showed experienced judges two routines on the vault. If they were told that the two athletes belonged to the same national team, the two routines received similar scores. But when they were believed to be from different teams, the scores were less similar.
There’s also been concern that some judges might be influenced by the opinions of other judges, in so-called “conformity bias”. Boen et al (2008) found that gymnastics judges’ scores were more even when they had feedback about each other’s scores. The effect continued even after feedback was no longer being provided, suggesting that once the judges felt reassured that they had given a “correct” response, they were no longer worried about standing out from the crowd.
The decisions of referees and umpires can sometimes be influenced by prior knowledge of the teams or players (Plessner & Haar 2006). It has been shown that the previous reputation of players can influence the decisions of referees in basketball (Lehman & Reifman 1987), in baseball (Rainey et al 1989). In football, Jones et al (2002) found that players with an aggressive reputation were penalised more severely than players with no such reputation.
A major benefit for a football team playing at home comes from crowd support. It seems that part of this benefit is from the effect that it has on the referee. Dawson et al (2007) found that the home side was more likely to get favourable decisions in terms of fouls and red cards. The amount of extra time allowed is higher when the home team is behind than when it is in front (Dohman 2008, Garicano et al 2005, Sutter & Kocher 2004).
Studies suggest that this home team bias is because of the influence of the home crowd (Bokyo et al 2007, Page & Page 2009), although it seems to have more of an effect of some referees than on others. With some referees, the amount of home bias is directly proportional to the size of the crowd, whereas for others the effect is constant, regardless of crowd size (Page & Page 2009). If there’s a running track around the pitch, the influence of the crowd on referees’ decisions seems to diminish (Buraimo et al 2008).
It could be that referees are simply alerted to the presence of a foul by crowd noise. Nevill et al (2002) found that referees looking at video footage (Liverpool v Leicester City) were much less likely to give advantage to the home team when the sound was turned off compared with when it was on.
Favouring teams or individuals of the same nationality as the official has been found in numerous sports, especially those that are judged subjectively. Clear national favouritism has been found in figure skating (Seltzer & Glass 1991, Whissell et al 1993, Campbell & Galbraith 1996), gymnastics (Ansorge & Scheer 1998, Ste-Marie 1996), ski jumping (Zitzewitz 2006), rhythmic gymnastics (Popovic 2000), Thai kick-boxing (Myers et al 2006) and synchronised diving (Emerson et al 2009). In all these sports, referees have been shown systematically to be giving advantage to competitors from their own countries, and the effect is significant, because the result often determined by the referee’s decision.
Even in sports where the result is not so closely tied to the decision of the referee, there has still been evidence of a national or local bias. Mohr & Larsen (1998) found that referees in Australian football were more likely to favour teams from their own states in matches against teams from another state.
At a national level, football, rugby and cricket usually have neutral officials. Page & Page (2010) looked at two cases where referees were allowed to officiate in inter-club matches where the team from their nation played a team from another nation. These were in rugby league the European Super League 2006 – 9 (mostly British teams with one French team), and in rugby union the Super 14 2009 (5 South African, 5 New Zealand and 4 Australian teams).
In Super 14, a referee with the same nationality of a team increased the score of that team by on average 5 points relative to when there was a neutral referee. The home team won 71% of its matches when the referee was of its own nationality, compared with 50% when the referee was of the nationality of the away team.
In Super League, the French team received on average 9 points more in a match when the referee was not English. They won 67% of their matches when the referee was Australian or French, compared with only 41% when the referee was English. The effect varied according to whether or not the match was televised. When the referee was English, the French team was much more successful when the match was on TV (59%) than when it wasn’t (30%).
The effect of favouritism was most pronounced when the decisions were critical. When there was an English referee, the French team received twice as many cards as the English team, but when the referee wasn’t English they received roughly the same number.
Page & Page also studied the rugby league Championship, which had one French team and mostly English referees. They looked at decisions involving whether or not the ball had been grounded in scoring a try. French teams had a lower proportion of positive decisions (79% against 93%).
Favouritism was also particularly strong when the score was close, with English and French referees favouring the side of their own nationality when it mattered most. In the Championship, when the difference between the sides was 4 points or less, the French team had only a 59% chance of getting a try validated, compared with 82% for the English team.
Because so many of the decisions made by officials are a matter of opinion, such as LBW decisions in cricket, the individual can justify to themselves that they made the correct decision according to the laws of the game, and will genuinely not be aware of their own bias. There are many factors that go into making a split-second decision, including the attitude of the players, the crowd or spectators, the personality of the official, and even their mind-set on the day.
It’s important therefore that during their training, officials are made aware of these factors, and are given as much practice (e.g. videos with crowd noise) and feedback as possible to enable them to improve their consistency. Because one thing seems clear: in many sports, officials’ decisions have a large effect on the result of the game.
David Donner
Some sports actually incorporate subjectivity into their laws. In rugby, for instance, the referee is the sole judge of whether or not advantage has been gained. In cricket, the umpire has to decide whether or not short-pitched bowling is unfairly intimidating, taking into account the batsman’s ability. Nevill et al (2002) showed 47 football situations on video to a set of referees. None of them received a unanimous verdict from the refs.
Personal style is undoubtedly a major factor in many decisions. For instance, in rugby, some referees may want to establish their authority early, whilst others may wish to allow the game to flow without being seen to be overly fussy. The referee might be influenced by previous incidents in the game, or even from a previous match between the same opponents. There may also be some benefit given to a side that’s losing heavily.
Trudel, Dionne and Bernard (1999), as well as Gilbert, Trudel & Bloom (1995), in assessing ice hockey penalties, concluded that referees, compared with players and coaches, attached greater importance to the context in which the infraction had occurred. Gilbert et al revealed that both the score and the time remaining in the game influenced decisions about whether or not to award penalties.
Diane Ste-Marie of the University of Ottawa has done a lot of research, especially in gymnastics, into how judgement can be affected by previous experience. She found that if judges were shown a performance on video with an error, they were more likely to see non-existent errors in the second tape. The effect lasted even if the second tape wasn’t seen until a week after the first one, so could affect an athlete performing in several rounds, or even if they’ve been seen in a warm-up. A similar effect has been found in figure skating.
Other assumptions made by officials can be just as erroneous. Damisch et al (2006) showed experienced judges two routines on the vault. If they were told that the two athletes belonged to the same national team, the two routines received similar scores. But when they were believed to be from different teams, the scores were less similar.
There’s also been concern that some judges might be influenced by the opinions of other judges, in so-called “conformity bias”. Boen et al (2008) found that gymnastics judges’ scores were more even when they had feedback about each other’s scores. The effect continued even after feedback was no longer being provided, suggesting that once the judges felt reassured that they had given a “correct” response, they were no longer worried about standing out from the crowd.
The decisions of referees and umpires can sometimes be influenced by prior knowledge of the teams or players (Plessner & Haar 2006). It has been shown that the previous reputation of players can influence the decisions of referees in basketball (Lehman & Reifman 1987), in baseball (Rainey et al 1989). In football, Jones et al (2002) found that players with an aggressive reputation were penalised more severely than players with no such reputation.
A major benefit for a football team playing at home comes from crowd support. It seems that part of this benefit is from the effect that it has on the referee. Dawson et al (2007) found that the home side was more likely to get favourable decisions in terms of fouls and red cards. The amount of extra time allowed is higher when the home team is behind than when it is in front (Dohman 2008, Garicano et al 2005, Sutter & Kocher 2004).
Studies suggest that this home team bias is because of the influence of the home crowd (Bokyo et al 2007, Page & Page 2009), although it seems to have more of an effect of some referees than on others. With some referees, the amount of home bias is directly proportional to the size of the crowd, whereas for others the effect is constant, regardless of crowd size (Page & Page 2009). If there’s a running track around the pitch, the influence of the crowd on referees’ decisions seems to diminish (Buraimo et al 2008).
It could be that referees are simply alerted to the presence of a foul by crowd noise. Nevill et al (2002) found that referees looking at video footage (Liverpool v Leicester City) were much less likely to give advantage to the home team when the sound was turned off compared with when it was on.
Favouring teams or individuals of the same nationality as the official has been found in numerous sports, especially those that are judged subjectively. Clear national favouritism has been found in figure skating (Seltzer & Glass 1991, Whissell et al 1993, Campbell & Galbraith 1996), gymnastics (Ansorge & Scheer 1998, Ste-Marie 1996), ski jumping (Zitzewitz 2006), rhythmic gymnastics (Popovic 2000), Thai kick-boxing (Myers et al 2006) and synchronised diving (Emerson et al 2009). In all these sports, referees have been shown systematically to be giving advantage to competitors from their own countries, and the effect is significant, because the result often determined by the referee’s decision.
Even in sports where the result is not so closely tied to the decision of the referee, there has still been evidence of a national or local bias. Mohr & Larsen (1998) found that referees in Australian football were more likely to favour teams from their own states in matches against teams from another state.
At a national level, football, rugby and cricket usually have neutral officials. Page & Page (2010) looked at two cases where referees were allowed to officiate in inter-club matches where the team from their nation played a team from another nation. These were in rugby league the European Super League 2006 – 9 (mostly British teams with one French team), and in rugby union the Super 14 2009 (5 South African, 5 New Zealand and 4 Australian teams).
In Super 14, a referee with the same nationality of a team increased the score of that team by on average 5 points relative to when there was a neutral referee. The home team won 71% of its matches when the referee was of its own nationality, compared with 50% when the referee was of the nationality of the away team.
In Super League, the French team received on average 9 points more in a match when the referee was not English. They won 67% of their matches when the referee was Australian or French, compared with only 41% when the referee was English. The effect varied according to whether or not the match was televised. When the referee was English, the French team was much more successful when the match was on TV (59%) than when it wasn’t (30%).
The effect of favouritism was most pronounced when the decisions were critical. When there was an English referee, the French team received twice as many cards as the English team, but when the referee wasn’t English they received roughly the same number.
Page & Page also studied the rugby league Championship, which had one French team and mostly English referees. They looked at decisions involving whether or not the ball had been grounded in scoring a try. French teams had a lower proportion of positive decisions (79% against 93%).
Favouritism was also particularly strong when the score was close, with English and French referees favouring the side of their own nationality when it mattered most. In the Championship, when the difference between the sides was 4 points or less, the French team had only a 59% chance of getting a try validated, compared with 82% for the English team.
Because so many of the decisions made by officials are a matter of opinion, such as LBW decisions in cricket, the individual can justify to themselves that they made the correct decision according to the laws of the game, and will genuinely not be aware of their own bias. There are many factors that go into making a split-second decision, including the attitude of the players, the crowd or spectators, the personality of the official, and even their mind-set on the day.
It’s important therefore that during their training, officials are made aware of these factors, and are given as much practice (e.g. videos with crowd noise) and feedback as possible to enable them to improve their consistency. Because one thing seems clear: in many sports, officials’ decisions have a large effect on the result of the game.
David Donner
Are You Blind Ref?
Quite a bit of research has been done on the visual requirements of different sports, but very little on the requirements for sports officials.
There are, of course, several different kinds of officials. For simplicity, I’ll put them in four main groups.
Recorders include cricket scorers, and those who measure distances and times in athletics. Line judges would include line umpires in tennis, but would also include some who can occasionally intervene in play, such as touch judges in rugby. Referees and umpires are an integral part of the game, often making an enormous number of decisions, as in cricket, rugby and football. Finally, judges give a rating to a performance, but are external to it, for instance in gymnastics, diving and figure skating.
Some officials will cut across these boundaries, such as tennis umpires. There are also other officials who are further removed from the performance, such as tournament referees, 3rd and 4th officials.
I'm going to be concentrating on those officials who have to make decisions, but even recorders rely on vision. Cricket scorers in particular have quite high visual demands as they are a long way from the action. Recognising batsmen under helmets from outside the boundary can be difficult, and may require other features to be found, such as the markings on the bats. Scorers also need to be careful that they are ready to acknowledge any signal from the umpire, and aren’t looking down at the scorebook at that moment.
All officials, therefore, should have regular eye examinations to ensure that their judgments aren’t being distorted through any defects in their vision. This should usually include an assessment of their field of vision, as significant defects could result in some of the action being missed completely.
Assuming that the official has a good standard of vision, if necessary corrected with either spectacles or contact lenses as appropriate, we can look at how vision is an integral part of the decision making process for sports officials.
We've already seen how perception can affect line decisions in tennis (see “You cannot be serious” blog). This same effect could also cause assistant referees to flag a player offside who isn’t, and an umpire give a narrow run out decision in favour of the batsman.
Tennis line umpires are in a more or less fixed position, but the positioning of officials can be a crucial factor in their decisions. Oudejans et al (2000) proposed that many incorrect offside decisions in football were as a result of the referee’s assistant being behind, rather than level with, the last defender. The Dutch researchers correctly predicted that this would lead to more wrong calls of offside than missed calls of actual offside. But presumably, this would depend on whether the attacker was on the far side of the defender or near side, as viewed by the official. So it could be that they were actually confirming Whitney’s theory of perceptual delay (described in “You cannot be serious”). Nevertheless, it must be the case that poor positioning would cause errors due to simple parallax, even if they don’t necessarily favour the defender.
One of the things that can help with positioning is anticipation. For instance, if a rugby referee can anticipate a likely drop goal attempt, they’re more likely to be able to get in position to be able to tell whether or not the kick is successful.
Ste-Marie (1998) expert gymnastics judges showed better anticipation than novice judges. All judges were more accurate when they had seen the same performance earlier. If there was some minor difference in the two performances (e.g. bent knees versus straight knees) they were less accurate, and if the second performance had a completely different element to the first, this produced the least accurate judgements.
So whilst correct anticipation can lead to improved judging, incorrect anticipation can lead to inaccurate (though rapid) judgements. Judges therefore need to be able to recognise when a new element has occurred, and take the necessary time to re-evaluate it. They also need to keep an open mind at all times. Ste-Marie found that if judges were shown a move with an error, they were more likely to see non-existent errors when the move was repeated a second time.
A difference that is often seen between experts and novices in sport is how they make better use of visual information in decision making. Expert tennis players, for instance, will focus on certain parts of their opponent’s body when determining the direction of their shot. Is there any evidence for officials doing this?
Well, there is some. In gymnastics, for instance, Bard et al (1980) found that expert judges watched different areas of the body than did novice judges. Sed (2008) found a similar result in basketball. When asked about their thoughts when watching a DVD of a match, expert basketball officials focused on specific areas of the court, whereas novice officials tended to watch the ball. This enabled the experts to anticipate better the movements of the players.
Smith & Millslagle (2008) used head-mounted cameras to assess the gaze fixation of elite and novice umpires in softball. They found that when the pitcher released the ball, the elite umpires’ gaze location was 100% on the ball, whereas the novices’ gaze location was only 55% on the ball.
Considering officials that are an official part of the game, such as rugby and football referees, there are a large number of decisions that need to be made during a game. A study of football referees during the EURO 2000 championships found that they made, on average, 137 observable decisions. That didn’t include all the unobservable decisions (approximately 60), such as deciding not to blow the whistle. Most of these decisions have to be made within time constraints. Australian Football League referees were found to have less than a second in which to make their decisions (McLennan & Omodei, 1996).
Cricket umpires generally have more time to make their decisions, but one exception is in determining whether the bowler has no-balled or not. The umpire has to decide very quickly whether or not the bowler’s feet are legally placed before switching gaze to pick up the flight of the ball in anticipation of a possible LBW decision.
The relevant Law begins “In the delivery stride, the front must land……” When I was training to become a qualified umpire, we had to learn this off by heart, and if our answers didn’t have the words “in the delivery stride” we would lose marks. But when you’re umpiring you don’t have time to think about the words, you have to instantly recognise whether the feet are in an allowed position or not. The same goes for a rugby referee when judging whether a tackle is legal or not.
The training of umpires has now improved, and much time is spent demonstrating feet positions, for example. The idea is that these images are stored in the visual memory, providing an instant comparison to be used on the field of play.
If we are to improve at something, we need some kind of feedback to judge whether or not we are actually improving. One of the few studies on the use of feedback for sports officials was by Jendrusch et al (2002) for tennis line judges. Electronic devices were used to assess where the ball landed. Those line judges who received accurate feedback about their decisions showed marked improvements compared with those who didn’t. They showed no general improvement in perceptual skills, but simply learned what to look at when making decisions. A similar system could be used to improve the accuracy of cricket umpire’s LBW decisions using Hawk-Eye.
If we want to improve the decision making of referees and umpires, it would be helpful to know whether this can only be done on the field of play, or whether video training can also be used. One attempt to do this has been by Brand et al (2009) with the SET - Schiedsrichter-Entscheidngs-Training (Referees Decision-making Training). Videos from a variety of competitions are shown, including the German Bundesliga and the UEFA Champions League. Each video is stopped after a crucial incident, usually a contact between two players, and the participant clicks with a mouse to indicate their decision. This system has been cleverly designed to enable several parameters to be changed, such as how much time is allowed to make decisions, and whether feedback about the correctness of the decision is given immediately or delayed. Extra information can also be inserted, such as shirt colour and crowd noise, to explore the extent to which irrelevant information is used (See “Is the ref biased?”).
They've found that it’s better to give immediate, rather than delayed, feedback on the correctness of decisions. This resulted in the most effective increases in decision accuracy.
One limitation with the SET is that the video clips were taken from external pitch side cameras, so do not give the referee’s actual view. This was also a limitation of a Canadian study in which video clips were shown to rugby referees (MacMahon 1999). The experienced referees wanted to know more information than was provided, and often felt the videos gave them a poor view. One answer would be to fit a referee with a head-mounted camera. Another specific problem was that the referees wanted to see whether there was going to be advantage or not, despite the fact that they were told to ignore the question of advantage.
Another use of video has been in point sparring, which is a scoring system used in some martial arts. The determination of whether or not a point has been scored can be a subjective decision by the referee. Krueger (2008) found, unsurprisingly, that first-time referees were significantly less accurate in their scoring compared with more experienced ones. More surprising, perhaps, was the finding that accuracy was generally less when the standards were higher and the two fighters were more evenly matched. This meant that in the finals, when, at least in theory, the two best fighters met, the accuracy of decisions was lowest.
They also found that a referee with 20 years’ experience was generally no more accurate than a referee with only 2 years’ experience. This suggests that experience without feedback can lead to a plateau effect. Virtually all the referees showed systematic errors that could be easily corrected. One referee occasionally awarded a point to obviously the wrong person, apparently confusing which fighter was which. Another was generally accurate, but would make several errors in a short period, suggesting lapses in concentration.
Just as ProBatter has been used to give England’s batsmen a realistic idea of what it’s like facing Test bowlers, virtual technology should in time be able to give officials experience in an environment where mistakes aren’t too costly. Important factors such as crowd noise could easily be incorporated.
In the meantime, I’m always surprised how little officials are used in players’ practice sessions. Not only would it give novices a chance to develop their experience, but established officials could use it to “get their eye in” before the start of the season.
This would also benefit the players. How many bowlers overstep in the nets? Would there be so many offences at the break down if there were referees at practice games?
A novel way of giving trainee officials relevant experience and feedback has been tried in the Australian Football League. First year umpires are given green shirts, and are monitored by an experienced referee during a game. They may be asked to concentrate on just one call, and may stay on the field for a limited amount of time, giving them a chance to reflect. In rugby union, for instance, a similar system might have trainees concentrating on the straightness of the throw or the spacing between players at the line out.
I’m sure a lot could be learned from time on the pitch with an experienced referee, learning how to look in the right places for likely offences.
David Donner
There are, of course, several different kinds of officials. For simplicity, I’ll put them in four main groups.
Recorders include cricket scorers, and those who measure distances and times in athletics. Line judges would include line umpires in tennis, but would also include some who can occasionally intervene in play, such as touch judges in rugby. Referees and umpires are an integral part of the game, often making an enormous number of decisions, as in cricket, rugby and football. Finally, judges give a rating to a performance, but are external to it, for instance in gymnastics, diving and figure skating.
Some officials will cut across these boundaries, such as tennis umpires. There are also other officials who are further removed from the performance, such as tournament referees, 3rd and 4th officials.
I'm going to be concentrating on those officials who have to make decisions, but even recorders rely on vision. Cricket scorers in particular have quite high visual demands as they are a long way from the action. Recognising batsmen under helmets from outside the boundary can be difficult, and may require other features to be found, such as the markings on the bats. Scorers also need to be careful that they are ready to acknowledge any signal from the umpire, and aren’t looking down at the scorebook at that moment.
All officials, therefore, should have regular eye examinations to ensure that their judgments aren’t being distorted through any defects in their vision. This should usually include an assessment of their field of vision, as significant defects could result in some of the action being missed completely.
Assuming that the official has a good standard of vision, if necessary corrected with either spectacles or contact lenses as appropriate, we can look at how vision is an integral part of the decision making process for sports officials.
We've already seen how perception can affect line decisions in tennis (see “You cannot be serious” blog). This same effect could also cause assistant referees to flag a player offside who isn’t, and an umpire give a narrow run out decision in favour of the batsman.
Tennis line umpires are in a more or less fixed position, but the positioning of officials can be a crucial factor in their decisions. Oudejans et al (2000) proposed that many incorrect offside decisions in football were as a result of the referee’s assistant being behind, rather than level with, the last defender. The Dutch researchers correctly predicted that this would lead to more wrong calls of offside than missed calls of actual offside. But presumably, this would depend on whether the attacker was on the far side of the defender or near side, as viewed by the official. So it could be that they were actually confirming Whitney’s theory of perceptual delay (described in “You cannot be serious”). Nevertheless, it must be the case that poor positioning would cause errors due to simple parallax, even if they don’t necessarily favour the defender.
One of the things that can help with positioning is anticipation. For instance, if a rugby referee can anticipate a likely drop goal attempt, they’re more likely to be able to get in position to be able to tell whether or not the kick is successful.
Ste-Marie (1998) expert gymnastics judges showed better anticipation than novice judges. All judges were more accurate when they had seen the same performance earlier. If there was some minor difference in the two performances (e.g. bent knees versus straight knees) they were less accurate, and if the second performance had a completely different element to the first, this produced the least accurate judgements.
So whilst correct anticipation can lead to improved judging, incorrect anticipation can lead to inaccurate (though rapid) judgements. Judges therefore need to be able to recognise when a new element has occurred, and take the necessary time to re-evaluate it. They also need to keep an open mind at all times. Ste-Marie found that if judges were shown a move with an error, they were more likely to see non-existent errors when the move was repeated a second time.
A difference that is often seen between experts and novices in sport is how they make better use of visual information in decision making. Expert tennis players, for instance, will focus on certain parts of their opponent’s body when determining the direction of their shot. Is there any evidence for officials doing this?
Well, there is some. In gymnastics, for instance, Bard et al (1980) found that expert judges watched different areas of the body than did novice judges. Sed (2008) found a similar result in basketball. When asked about their thoughts when watching a DVD of a match, expert basketball officials focused on specific areas of the court, whereas novice officials tended to watch the ball. This enabled the experts to anticipate better the movements of the players.
Smith & Millslagle (2008) used head-mounted cameras to assess the gaze fixation of elite and novice umpires in softball. They found that when the pitcher released the ball, the elite umpires’ gaze location was 100% on the ball, whereas the novices’ gaze location was only 55% on the ball.
Considering officials that are an official part of the game, such as rugby and football referees, there are a large number of decisions that need to be made during a game. A study of football referees during the EURO 2000 championships found that they made, on average, 137 observable decisions. That didn’t include all the unobservable decisions (approximately 60), such as deciding not to blow the whistle. Most of these decisions have to be made within time constraints. Australian Football League referees were found to have less than a second in which to make their decisions (McLennan & Omodei, 1996).
Cricket umpires generally have more time to make their decisions, but one exception is in determining whether the bowler has no-balled or not. The umpire has to decide very quickly whether or not the bowler’s feet are legally placed before switching gaze to pick up the flight of the ball in anticipation of a possible LBW decision.
The relevant Law begins “In the delivery stride, the front must land……” When I was training to become a qualified umpire, we had to learn this off by heart, and if our answers didn’t have the words “in the delivery stride” we would lose marks. But when you’re umpiring you don’t have time to think about the words, you have to instantly recognise whether the feet are in an allowed position or not. The same goes for a rugby referee when judging whether a tackle is legal or not.
The training of umpires has now improved, and much time is spent demonstrating feet positions, for example. The idea is that these images are stored in the visual memory, providing an instant comparison to be used on the field of play.
If we are to improve at something, we need some kind of feedback to judge whether or not we are actually improving. One of the few studies on the use of feedback for sports officials was by Jendrusch et al (2002) for tennis line judges. Electronic devices were used to assess where the ball landed. Those line judges who received accurate feedback about their decisions showed marked improvements compared with those who didn’t. They showed no general improvement in perceptual skills, but simply learned what to look at when making decisions. A similar system could be used to improve the accuracy of cricket umpire’s LBW decisions using Hawk-Eye.
If we want to improve the decision making of referees and umpires, it would be helpful to know whether this can only be done on the field of play, or whether video training can also be used. One attempt to do this has been by Brand et al (2009) with the SET - Schiedsrichter-Entscheidngs-Training (Referees Decision-making Training). Videos from a variety of competitions are shown, including the German Bundesliga and the UEFA Champions League. Each video is stopped after a crucial incident, usually a contact between two players, and the participant clicks with a mouse to indicate their decision. This system has been cleverly designed to enable several parameters to be changed, such as how much time is allowed to make decisions, and whether feedback about the correctness of the decision is given immediately or delayed. Extra information can also be inserted, such as shirt colour and crowd noise, to explore the extent to which irrelevant information is used (See “Is the ref biased?”).
They've found that it’s better to give immediate, rather than delayed, feedback on the correctness of decisions. This resulted in the most effective increases in decision accuracy.
One limitation with the SET is that the video clips were taken from external pitch side cameras, so do not give the referee’s actual view. This was also a limitation of a Canadian study in which video clips were shown to rugby referees (MacMahon 1999). The experienced referees wanted to know more information than was provided, and often felt the videos gave them a poor view. One answer would be to fit a referee with a head-mounted camera. Another specific problem was that the referees wanted to see whether there was going to be advantage or not, despite the fact that they were told to ignore the question of advantage.
Another use of video has been in point sparring, which is a scoring system used in some martial arts. The determination of whether or not a point has been scored can be a subjective decision by the referee. Krueger (2008) found, unsurprisingly, that first-time referees were significantly less accurate in their scoring compared with more experienced ones. More surprising, perhaps, was the finding that accuracy was generally less when the standards were higher and the two fighters were more evenly matched. This meant that in the finals, when, at least in theory, the two best fighters met, the accuracy of decisions was lowest.
They also found that a referee with 20 years’ experience was generally no more accurate than a referee with only 2 years’ experience. This suggests that experience without feedback can lead to a plateau effect. Virtually all the referees showed systematic errors that could be easily corrected. One referee occasionally awarded a point to obviously the wrong person, apparently confusing which fighter was which. Another was generally accurate, but would make several errors in a short period, suggesting lapses in concentration.
Just as ProBatter has been used to give England’s batsmen a realistic idea of what it’s like facing Test bowlers, virtual technology should in time be able to give officials experience in an environment where mistakes aren’t too costly. Important factors such as crowd noise could easily be incorporated.
In the meantime, I’m always surprised how little officials are used in players’ practice sessions. Not only would it give novices a chance to develop their experience, but established officials could use it to “get their eye in” before the start of the season.
This would also benefit the players. How many bowlers overstep in the nets? Would there be so many offences at the break down if there were referees at practice games?
A novel way of giving trainee officials relevant experience and feedback has been tried in the Australian Football League. First year umpires are given green shirts, and are monitored by an experienced referee during a game. They may be asked to concentrate on just one call, and may stay on the field for a limited amount of time, giving them a chance to reflect. In rugby union, for instance, a similar system might have trainees concentrating on the straightness of the throw or the spacing between players at the line out.
I’m sure a lot could be learned from time on the pitch with an experienced referee, learning how to look in the right places for likely offences.
David Donner
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