VAR would have had 4% effectiveness in Champions League matches

Created on:
May 25, 2022

Summary

  • Analysed 12 Champions League matches (round of 16).
  • Found 132 diving events, 59% identified by the referee.
  • 54 events went unidentified, 15 of them had an unfair impact on the game.
  • VAR could have been invoked 2 times, effectiveness of 4%.
  • 79 players from all the teams engaged in diving, roughly 44% of players on the field.
  • Analysis used the 6 traits of dives based on a 2010 study by Paul H. Morris & David Lewis from University of Portsmouth, UK.
  • Full dataset is available here.

While VAR will help solve the most controversial events there is still a long way to go in order to establish honesty and fair play as the new normal in football. We propose 2 solutions to continue improving fairness in the game, fortunately they both can be applied in parallel:

  1. Continue expanding the use of VAR and use our measurement model to find ways to extend its positive impact to more plays during matches.
  2. Encourage players to demonstrate honesty and integrity when they are on the field to decrease the number of dives and the negative impact from them.

Analysis objectives

VAR will be used in the 2018 World Cup in Russia and we celebrate that decision! The use of technology in football is long overdue. It has paid off in other sports, we look forward to seeing it pay off in our beloved sport too. Nevertheless, the scope of VAR could still be too limited when looking at the overall diving practice given that it can only be invoked in particular cases:

  • Goals (and incidents leading up to them)
  • Penalties
  • Red cards
  • Cases of mistaken identity

Our Champions League analysis have 3 objectives:

  1. Test our measurement model on a real life scenario.
  2. Understand the extent of the diving practice in this league.
  3. Understand how much VAR would have helped to keep actions and decisions fair.

Analysis outcomes

Overall results

Found 132 diving events, 59% of which were identified by the Referee. A portion of the rest (34) was identified by a video replay and the rest (20) were inconclusive, meaning replay was not enough to prove or disprove a dive.

Negative impact on matches

The events that were not identified by the referee produced unfair impact on the matches in 15 occasions. There were 11 cards (1 red), 2 goals scored and 2 winner changes (the diver’s team went from losing the game to a tie).

Match breakout

Diving happened in all matches:

But unfair impact was condensed in 6 matches:

The 2 events that changed winners were:

Juventus vs Tottenham

  • Inconclusive play between Dele Alli and Giorgio Chiellini. Both players end up falling. There’s reasonable doubt about contact being the cause of the fall but video replay is not enough to prove or disprove.
  • Play leads to a free kick, a goal is scored and Tottenham ties the game 2-2.
  • VAR could NOT have been invoked in this case.

Real Madrid vs PSG

  • Toni Kroos gets pulled from behind, then falls to the front. Lack of ballistic continuity given that the pull and the fall go in opposite directions. Toni Kroos falls in archer’s bow pose, one of the characteristic traits of dives.
  • Play leads to a penalty, a goal is scored and Real Madrid ties the game 1-1.
  • VAR could have been invoked in this case.

Team breakout

Diving was practiced by all the teams but only half of them produced unfair impact on their matches.

Player breakout

79 players engaged in diving, 80% of them with 1 or 2 dives (counting identified and inconclusive dives), 16 players dived 3 times of more. Disclaimer: Dive count should be weighted against effective play time to enable fair comparison between players.

VAR effectiveness

VAR was not used in these Champions League matches, but had it been used it would have helped analyse only 2 events, equivalent to 4% effectiveness.

Conclusions

While VAR is great effort to contain the negative impact of dishonesty on the field, it will help solve only the most impactful events at the bottom of the funnel. Many other dives causing other types of impact on the game will still go unnoticed.

We propose 2 ways to improve this situation addressing the problem bottom-up and top-down at the same time:

  • Extend the positive impact from VAR into more events at the bottom of the funnel. The measurement model we propose can help finding ways to improve this technology.
  • Decrease the number of events at the top of the funnel, in other words, decrease the number of diving events. We hope our #StopDiving effort will help by encourage players to always demonstrate honesty and integrity on the field.

Analysis methodology

Sample dataset

We analysed both legs of these matches (total of 12 matches):

  • Juventus vs Tottenham
  • Real Madrid vs PSG
  • Porto vs Liverpool
  • Chelsea vs Barcelona
  • Bayern Munich vs Besiktas
  • Sevilla vs Manchester United

Metrics

We tracked both quantitative and impact metrics

Quantitative metrics:

  • Number of dives identified by the referee.
  • Number of dives not identified by the referee but later identified by a video replay.
  • Number of possible dives not identified by the referee or by a video replay.

Impact metrics:

  • Possession changed
  • Card produced
  • Goal scored
  • Winner change

See full details on our measurement model here.

Rubric

We used the 6 traits to identify dives based on a 2010 study by Paul H. Morris & David Lewis from University of Portsmouth, UK. And we used these rubrics to keep tracking consistent across matches:

Tracked:

  • Identified by Referee: A player falls to the ground, explicitly asks for a fault and the referee doesn’t concede, no replay needed.
  • Identified by Video: A player falls to the ground, the referee concedes but through replay at least one of the 6 traits is clearly recognized.
  • Inconclusive: A player falls to the ground, the referee concedes, there’s reasonable doubt on one of the 6 traits but replay is not good enough to prove or disprove.

Not tracked

  • Consistent: A player falls to the ground, the referee concedes, there is contact and there’s consistency in nursing the body part exposed to the contact. Non of the other traits is clearly recognized. Do not track even if there’s exaggerated reaction by the falling player.
  • No replay: A player falls to the ground, the referee concedes but there’s no replay to check for traits.
Header graphic, UEFA Champions League logo and UEFA Champions League brand are property of UEFA.

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