;

Opta's event definitions

Posted 1st September 2018

salah advanced analytics.png

Globally consistent definitions

Opta's key strength is the ability to provide in-depth, accessible data that is consistent across the globe. Without this certainty, Opta's player and team statistics can be far less valuable and there would be a danger that different leagues would be analysed in conflicting ways, rendering proper player comparison invalid.

To avoid this, Opta have a long-established a consistent list of 'Event Definitions' in football that are adhered to across all data collection centres.

 

 

Opta Glossary

This is a list of the main football events logged by Opta:

Goals/Shots

Goal/Own Goal
Different governing bodies have different rules, and where possible Opta works with the relevant people to reflect their official decisions on goal scorers.

Regarding deflections, normally a goal is awarded if the original attempt is on target. An own goal is usually awarded if the attempt is off target and deflected into the goal by an opponent.

Shot on target
A shot on target is defined as any goal attempt that:
• Goes into the net regardless of intent.
• Is a clear attempt to score that would have gone into the net but for being saved by the goalkeeper or is stopped by a player who is the last-man with the goalkeeper having no chance of preventing the goal (last line block).

Shots directly hitting the frame of the goal are not counted as shots on target, unless the ball goes in and is awarded as a goal.

Shots blocked by another player, who is not the last-man, are not counted as shots on target.

Shot off target
A shot off target is defined as any clear attempt to score that:
• Goes over or wide of the goal without making contact with another player.
• Would have gone over or wide of the goal but for being stopped by a goalkeeper's save or by an outfield player.
• Directly hits the frame of the goal and a goal is not scored.

Blocked shots are not counted as shots off target.

Blocked Shot
A blocked shot is defined as any clear attempt to score that:
• Is going on target and is blocked by an outfield player, where there are other defenders or a goalkeeper behind the blocker.

Includes shots blocked unintentionally by the shooter’s own team mate.

Clearances off the line by an opposition player (last line blocks) are counted as shots on target and do not get counted as a blocked shot.

Chance conversion/Goals-to-shots ratio
A calculation of goals scored divided by shots attempted (excluding blocked attempts and own goals).

Shooting Accuracy
A calculation of Shots on target divided by all shots (excluding blocked attempts and own goals).

Pattern of play for Goals/Shots
Set Piece goals/attempts are those where the ball starts from a dead ball situation such as a corner, a free kick, a penalty or a Throw-in and results in a shot before the phase of play has broken down into open play.

There are seven patterns of play, one of which must be assigned to each attempt.
• Regular – an attempt created from an open play attack
• Set piece – an attempt created where the ball starts from an indirect free kick dead ball situation
• Throw in – an attempt created from a throw in
• Direct free kick – an attempt created from a direct free kick situation
• Direct corner – a goal scored directly from the corner
• Corner – an attempt created from a corner situation
• Fast break – an attempt created after the defensive quickly turn defence into attack winning the ball in their own half (counter attack)
• Penalty – The penalty attempt itself, any follow up shot would be classed as set piece. Passed penalties are also counted as ‘Penalty’ pattern of play.
The relevant pattern of play is assigned to a shot before the phase of play has broken down into open play.

The exact point at which it becomes open play is usually clear but set pieces and corners which are cleared and then the ball is put straight back into the penalty area are still deemed to be part of the set play as the defending team is still positioned to deal with the set play. This rule includes the free kicks, corners, throw ins and penalties.

Big Chances
A situation where a player should reasonably be expected to score, usually in a one on one scenario or from very close range when the ball has a clear path to goal and there is low to moderate pressure on the shooter. Penalties are always considered big chances.

Chance missed
A big chance opportunity when the player does not get a shot away, typically given for big chance attempts where the player shooting completely misses the ball (air shot) but can also be given when the player has a big chance opportunity to shoot and decides not to, resulting in no attempt occurring in that attack.

Direct Free Kick for Goals/Shots
Direct free kick shots are any attempts created directly from the free kick itself (unassisted).

Body Part for Goals/Shots
The following four body parts are collected: Right foot, left foot, head and other. Foot includes any connection with the leg.

Location for Goals/Shots
The position of the ball, when the shot is taken (shot origin).

Any event happening on a line, will be considered inside that area. For example, a shot on the 18-yard line will count as being inside the box.

Goal Assist
The final touch (pass, pass-cum-shot or any other touch) leading to the recipient of the ball scoring a goal. If the final touch (as defined in bold) is deflected by an opposition player, the initiator is only given a goal assist if the receiving player was likely to receive the ball without the deflection having taken place. Own goals, directly taken free kicks, direct corner goals and penalties do not get an assist awarded.

Fantasy Goal Assist
Additional fantasy assist types are collected, but not counted as normal goal assists. The following types of fantasy assists are collected:
• Heavily deflected pass or cross
• Shot on target saved, rebound scored
• Shot blocked, rebound scored
• Shot hit woodwork, rebound scored
• Penalty won
• Free kick won by foul
• Free kick instigated by forced handball
• Instigating own goal usually through shot/pass/cross

Second Assist
A pass/cross that is instrumental in creating a goal-scoring opportunity, for example a corner or free-kick to a player who then assists an attempt, a chance-creating through ball or cross into a dangerous position.

xG/xA

Expected Goals
Expected Goals (xG) measures the quality of a shot based on several variables such as assist type, shot angle and distance from goal, whether it was a headed shot and whether it was defined as a big chance. Adding up a player or team’s expected goals can give us an indication of how many goals a player or team should have scored on average, given the shots they have taken.

Expected Assists
Expected assists (xA) measures the likelihood that a completed pass will become a goal assist. It considers several factors including the type of pass and end-point and length of pass. Adding up a player or team’s expected assists gives us an indication of how many assists a player of team should have had based on their build up and attacking play.

Passes

Key Pass
The final pass or pass-cum-shot leading to the recipient of the ball having an attempt at goal without scoring.

Chances Created
Assists plus Key passes.

Pass
Any intentional played ball from one player to another. Passes include open play passes, goal kicks, corners and free kicks played as pass – but exclude crosses, keeper throws and throw-ins.

Opta adds a whole range of qualifiers to each pass event, so that various things can be measured
• Chipped pass – a lofted ball where there is a clear intended recipient, must be over shoulder height and using the passes height to avoid opposition players.
• Headed pass – a header where there is a clear intended recipient
• Launch – a long high ball into space or into an area for players to chase or challenge for the ball
• Flick-on – a glancing pass with head or foot onto a team mate where the ball is helped on in the same general direction
• Pull back – a pass inside the penalty area which is pulled back from the goal-line to the centre of the penalty area
• Lay-off – a first time pass away from goal when there is pressure on the passer (Typically played by a forward) with one touch when they have their back to goal
• Through Ball – a pass splitting the defence for a team-mate to run on to.
• Tap pass – a short pass after a dead ball situation which cannot have a lost outcome.
Each pass is logged with X and Y co-ordinates for its point of origin and destination.

This allows Opta to log the following:
• Passes broken down area of the pitch for example by own half/opposition half or defensive/middle/final third or left/right/centre
• Passes broken down by half, for example short/long, short medium/long
• Pass direction, for example backwards/sideways/forwards.

Of course, the event-based nature of the data is such that you can calculate any combination such as chipped passes over 20 yards in the final third that go sideways.

Cross
Any intentional played ball from a wide position intending to reach a team mate in a specific area in front of the goal.

Pass completion
This is simply a formula where successful passes are divided by total attempted passes in whichever combination of passes is selected. Usually, pass completion excludes crosses.
Crosses are usually treated separately and crossing success is the percentage of successful crosses out of the total attempted.

A completed pass is a pass which goes to a team mate directly without a touch from an opposition player.

Touches

Touches
A sum of all events where a player touches the ball, so excludes things like Aerial lost or Challenge lost.

Touch/Unsuccessful touch
When the ball bounces off a player and there is no intentional pass, we award a touch. When a player mis-controls the ball with a poor touch, we award an unsuccessful touch. Also used for mishit shots which go backwards towards a player’s own goal.

Dribbles/Take-ons
This is an attempt by a player to beat an opponent when they have possession of the ball. A successful dribble means the player beats the defender while retaining possession, unsuccessful ones are where the dribbler is tackled. Opta also collects attempted dribbles where the player overruns the ball with a heavy touch when trying to beat an opposition player.

Tackle
A tackle is defined as where a player connects with the ball in a ground challenge where he successfully takes the ball away from the player in possession.

The tackled player must clearly be in possession of the ball before the tackle is made.
• A tackle won is deemed to be where the tackler or one of his team-mates regains possession as a result of the challenge, or that the ball goes out of play and is “safe”.
• A tackle lost is where a tackle is made but the ball goes to an opposition player.

Both are deemed as successful tackles however, the outcome of the tackle (won or lost) is different based on where the ball goes after the tackle.

It is not a tackle, when a player cuts out a pass by any means.

Missed Tackles
This is where a player attempts to challenge for the ball and does not make it – it is calculated by adding fouls with an attempted tackle qualifier to the number of times a player is beaten by a dribble (challenge lost).

Clearance
This is a defensive action where a player kicks the ball away from his own goal with no intended recipient.

Interception
This is where a player reads an opponent’s pass and intercepts the ball by moving into the line of the intended pass.

Blocked pass
When a player tries to cut out an opposition pass by any means. Similar to an interception except there is much less reading of the pass.

Block
This is where a player blocks a shot on target from an opposing player.

Other categories

Recovery
This is where a player recovers the ball in a situation where neither team has possession or where the ball has been played directly to him by an opponent, thus securing possession for their team.

Shield ball out of play
Where a player shields the ball from an opponent and is successful in letting it run out of play. Can be offensive (to win a corner or throw in up field) or defensive (winning a throw in or goal kick).

Error
When a player makes an error, which leads to a goal or shot conceded. Also used for spills and attempted claims or saves by a goalkeeper which directly leads to a second attempt to score.

Hit Woodwork
Hit woodwork is given in situations where the ball hits the frame of the goal, except goals that hit the frame before going into the net.
Any shot that hits the frame multiple times (e.g. bar and left post) only count as hitting the woodwork once.

Hit woodwork is always collected for the attacking team (and the player, who performed the last action), even when the ball hits the frame coming from a defensive back pass.

Foul conceded
A foul conceded is defined as any infringement that is penalised as foul play by a referee.

Offsides are not given as a foul conceded.

Foul won
A foul won is defined as where a player wins a free kick or penalty for their team after being fouled by an opposing player.

There is no foul won for a handball, dive, back pass, illegal restart, dissent, GK 6-second violation or obstruction where a free kick is conceded.

• Handball – a deliberate hand ball by an opposition player
• Dive – a deliberate attempt for an opposition player to deceive the referee and win a free kick
• Back pass – a pass picked up by a goalkeeper when played from a team mate
• Illegal restart – an opposition player has consecutive touches directly after a dead ball situation
• Dissent – a player shows dissent towards a match official
• GK 6-second violation – when a goalkeeper picks up the ball and holds onto it longer than 6 seconds
• Obstruction – a player traps the ball between his legs in an attempt to stop an opposition player from playing the ball.

Penalty (won, conceded and taken)
A penalty is collected on the foul conceded (team and player). A foul won resulting in a penalty is only collected for players and doesn’t include handballs instigated. The penalty taken is collected as a shot or penalty pass (team and player).

Offside
Awarded to the player deemed to be in an offside position where a free kick is awarded. If two or more players are in an offside position when the pass is played, the player considered to be most active and trying to play the ball is given offside.

Offside Provoked
The deepest player in the defensive line when an offside has been given.

Out
When the ball has left the field of play for a goal kick or throw in (excluding corners).

Corner (won, lost and taken)
When the ball has left the field of play resulting in a corner. A corner won is collected for the team being awarded a corner, and corner lost for the team conceded a corner for the opposition team. A corner taken is added when the player taking the corner has carried out the action, usually a cross or a pass.

Start Delay
When the referee stops the game, typically for a player receiving treatment for an injury or the referee requires assistance from the VAR.

End Delay
When the referee restarts the game after a delay.

Injury time announced
The injury time announcement held up by the 4th official at the end of the 1st and 2nd half.

Cards
Cards are collected as yellow, 2nd yellow or red card. Where possible we cross-check cards against official (referee) reports to match the official statistics – unless these are clearly incorrect.

Disciplinary Points
For Opta Discipline tables, we award one point per foul conceded, three points per yellow card and six per red card. For Referees’ tables we also add three points per penalty awarded.

Sequences
Sequences are defined as passages of play which belong to one team and are ended by defensive actions, stoppages in play or a shot.
• Sequence Time: Time in seconds of a sequences
• Passes: Number of passes in a sequence
• Progress: Distance in metres the ball moved towards opponent goal line during the sequences
• Length: Total distance in metres the ball travelled during the sequence
• Speed: Length divided by sequence time (average speed of ball movement during sequence)
• Direct Speed: Progress divided by sequence time (average speed of ball movement towards opponent goal line during sequence)
• Width: Distance in metres between leftmost point in sequence and rightmost point in sequence
• Absolute Width: Furthest distance in metres ball is away from centre of the pitch in a sequence
• Involvement: Number of sequences that a player was involved in, involvement is defined as a player having at least one touch in the sequence

Possessions
Possessions are defined as one or more sequences in a row belonging to the same team. A possession is ended by the opposition gaining control of the ball.

Defensive Coverage
Defensive Coverage measures the area of defensive responsibility implied by a player’s defensive actions during a match. The corresponding output consists of a series of coordinates which define a polygon of the player’s defensive zone, as well as the area (in metres squared) of that zone.

Duels

Duel
A duel is an 50-50 contest between two players of opposing sides in the match. For every Duel Won there is a corresponding Duel Lost depending on the outcome of the contest.

Aerial Challenge won – Aerial Challenge lost
This is where two players challenge in the air against each other. The player that wins the ball is deemed to have won the duel. When more than two players are involved the player closest to the duel winner is given an Aerial Duel lost.

Successful Take-on/Dribble – Challenge lost
The player who has been beaten is given a Challenge lost if they do not win the ball.

Tackle – Unsuccessful Take-on/Dispossessed
A tackle is awarded if a player wins the ball from another player who is in possession. If he is attempting to beat the tackler, the other player will get an unsuccessful Take-on. If he is in possession but not attempting to “beat” his man, then he will get a dispossessed.

Smother – Unsuccessful Take-on
A goalkeeper who comes out and claims the ball at the feet of a forward gets a smother, similar to a tackle, however, the keeper must hold onto the ball to award a smother.

Foul won – Foul conceded
The player winning the foul is deemed to have won the duel and the player committing the foul having lost the duel.

Goalkeeper

Save
A goalkeeper preventing the ball from entering the goal with any part of his body when facing an intentional attempt from an opposition player.
Saves have the following attributes:
• Body part - Hands/Feet/Body
• Save type - Caught/Collected/Parried Safe/Parried Danger area/Fingertip
• Goalkeeper position - Diving/Standing/Reaching/Stooping

Clean Sheet
A player or team who does not concede a goal for the full match.

Penalty faced
We log which way a goalkeeper dives regardless of the outcome of the penalty.
• Diving left
• Diving right
• Standing

Catch
A high ball played into the penalty area that is caught by the goalkeeper.

Punch
A high ball that is punched clear by the goalkeeper. The keeper must have a clenched fist and attempting to clear the high ball rather than claim it.

Drop
A high ball where the goalkeeper tries to catch the ball, he gets his hands on the ball but drops it from his grasp.

Cross not claimed
When a goalkeeper comes off his goal line to claim a high ball (attempting a catch) and misses the ball.

Catch Success
The percentage of high balls played into penalty area, that a goalkeeper tries to deal with where he is successful – Catches + Punches divided by total high balls he came for.

Keeper Sweeper
A keeper sweeper is given anytime a goalkeeper anticipates danger and rushes off their line to try to either cut out an attacking pass (in a race with the opposition player) or to close-down an opposition player.

A keeper sweeper is defined if:
• The keeper rushes out to at least the edge of his area.
• There must be at least some pressure from the opposition forward racing to the ball
• The keeper reacts quickly and reads the play

Keeper pick up
When the goal keeper picks up the ball and his side regain possession, similar to recovery, however, the goal keeper picks the ball up.

 

Share: