Will the Brazilians be jammed on the mundial?

Brazil is a favorite of the World Cup that begins tomorrow in this country. This is evidenced by statistical studies (for example, the recent Goldman Sachs report ), almost all bookmakers put it on it. The result of one football match may depend on a variety of factors: on the physical form of players, on the tactics chosen by coaches for the match, on the support of the fans, from the decisions of the arbitrator and, in the end, from good luck in the implementation of the assembled moments. At a tournament distance one month, winning the Cup at the expense of one good luck will not work. However, the Brazilians have one advantage over the rest of the teams - they play at home. But how important is the home field factor in football victories? This question attracted the attention of economists.

A team playing the match at home can have several advantages. Firstly, guests get tired during the air travel. Secondly, the usual parameters of the football field do not require adaptation time. Thirdly, the support of fans can play an important role. Fourth, fans can exert psychological pressure on the referee, whistling every time he makes a “wrong” decision. The last factor became the subject of study by Ryan Boyko, Adam Boyko and Mark Boyko. In an article published in 2007, the authors appreciated whether there is a bias (intentional or involuntary) in the actions of football judges in favor of home teams. The database includes the matches of the English Premier League, played in 1992-2006. As a minimum threshold in the number of meetings held by the judge, the level of elimination of 25 games was chosen (it is impossible to draw substantial conclusions regarding the actions of judges who worked in just several matches). This criterion is satisfied with 50 referees. For each referee, the average characteristics (clogged and missed balls of home and guest teams, yellow and red cards of the owners and guests, as well as the hosts and guests of the penalty) for all the matches that he served.
Statistics on the average number of punishments are presented in the table.

Statistics on the average number of punishments for the match

	Home teams	Guest teams
Yellow cards	1.171	1.621
Red cards	0.056	0.094
Penalty	0.102	0.058

Source: Boyko Rh, Boyko AR, Boyko Mg (2007) Referee Bias Contributees to Home Advantage in English Premiership Football. Journal of Sport Sciences, 25 (11), 1185–1195.

The average difference of the home team clogged and missed balls for each of the 50 judges

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The average difference of clogged and missed balls for each judge

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The average difference of clogged and missed balls for all judges

Source: Boyko Rh, Boyko AR, Boyko Mg (2007) Referee Bias Contributees to Home Advantage in English Premiership Football. Journal of Sport Sciences, 25 (11), 1185–1195.

It would seem that the data confirm the hypothesis that the judges are favorable to home teams - the teams of guests are more often punished, and only at two of the fifty judges of the teams have a positive balance of clogged and missed balls. However, according to the above data, two hypotheses cannot be distinguished from each other: the teams of the house play better, and therefore they are more often violated by the rules, or really some judges help the hostess teams, as a result of which home teams improve. In order to trace individual arbitrators by the influence of the home match factor, the authors include parameters in their model that characterize the strength of each team in home and guest games. To analyze the meeting between the two teams, the average number of the goals of the house’s teams scored and missed and on the exit in all games of the season, except for the match between these teams, is calculated. These parameters reflect the average attacking and defensive potentials of the team. Researchers are interested in how much the decision adopted by the this specific judge reject the decision in this match, as well as the meeting of the meeting expected during these indicators of the game of opponents of the house and away. Simply put, now in home and outbound matches against Manchester United or against Blackpool the “norm” of violations will vary. It turns out that after the introduction of this amendment, the displacement of decisions of many referees in favor of home teams still takes place.
Nevertheless, the conclusions of the authors are not the final sentence to professional football arbitrators. Simon Cooper and Stefan Shimansky in the book “Footballonomics” give a link to study the Buriamo tunda, in which he limited himself to considering a narrower base of the matches of the English Premier League for 2002-2006 and did not find bias in the work of English judges. It is possible that over time, the class of judges grew up and they began to work more objectively. In addition, criticism of the methodology used in the article we are considering can be found in the work of Ron Johnston .
How impartial judge will be the Brazilians, we will see very soon. In any case, statistics gives the hostesses of the championship solid chances of success: in 6 of the 19 previous championships, the country - the organizer of the competition.