FOOTBALL has a remarkable capacity for causing arguments. Introducing a video-assistant referee (VAR) was meant to solve many of them. If anything, it has intensified the bickering. The system is being used in the World Cup for the first time, after trials in a handful of domestic leagues in the last 12 months. It is supposed to alert the on-field referee if he has made a “clear and obvious error” when awarding a goal, a penalty or a red card. That, alas, has proved a vague instruction.

Thus far in the World Cup the VAR has frequently intervened when players have been tripped in the penalty box. But he has remained silent when they have had their shirts tugged or arms held, both of which are considered fouls if done “using excessive force”. Fans, pundits and players have quarrelled over which tussles should have been penalised. Some think that the entire video-replay system is a waste of time, due to the subjectivity of the laws. Among their number is Carlos Queiroz, Iran’s manager, who accused officials of “intellectualising the game” (after his side had a goal correctly ruled out for offside).

Other onlookers believe that the VAR catches enough mistakes to be worthwhile. Officials in Germany and Italy, two of the countries to test the system in their domestic leagues, have admitted that the VAR still misses some fouls, but also claim that the system has reduced errors by 80%. Similarly the International Football Association Board (IFAB), which controls the laws of the game, reports that just 1.1% of decisions made using the VAR are wrong, compared to 7% without. Furthermore, it finds that the video replays take up just 1% of playing time, compared to 28% for set-piece stoppages.

On one thing most fans do agree: the VAR is causing a substantial increase in penalties, which are awarded for fouls near the goal. After 32 World Cup matches, marking the halfway point, referees have awarded 16 spot-kicks, which is twice the usual rate for the tournament. Six of them were given after the VAR intervened. Under the old system, as the

New York Times has noted

, the penalty rate would have been little different to the frequency seen in other tournaments.

But when The Economist looked at the six countries that have introduced the VAR system for all games in their domestic leagues—Germany, Italy, Portugal, America, Australia and South Korea—we found no evidence of a spike in penalties. That suggests that for every extra spot kick that the VAR has spotted, there is another that he has cancelled.

In the World Cup, however, only one penalty has been overturned so far. That was when Neymar, a Brazilian forward, flopped to the turf in the match against Costa Rica, and the VAR ruled that there had not been enough contact to justify the penalty.

All this suggests that the recent surge in World Cup spot kicks, from a historical average of one every four games, to one every two this year, is due to an unusual increase in clumsy tackles near the goal.

Some think the VAR may help reduce referees’ tendency to favour of the home team, influenced perhaps by a partisan crowd. Various studies have found evidence of such a bias across many sports. The introduction of the VAR in the Italian league did, indeed, appear to reduce penalties in favour of home teams. But there was no similar pattern across all six countries. This suggests that when comes to penalties an official in a remote bunker with access to video replays is just as likely as his colleague holding the whistle to rule in favour of the home team.