Monday, December 2, 2019

Home Field Advantage and other Lazy Assumptions

An amazing thing happened in the baseball World Series finals this year. The amazing thing was not that the Americans finally worked out that World Series is a ridiculous title for a tournament with just one token Canadian team playing in a sport that nobody out of the US, northern Latin America and Japan and Korea have any knowledge of. No, that lazy assumption persists. The amazing thing was that the away team won all seven matches. In over 1000 play off series, that had never happened before.

I would like to claim that the amazing thing is that most pundits thought this was amazing. Because home field advantage in most sports has been vanishing before our eyes, while we still make the lazy assumption that it is a large factor.

Here is a bit more evidence. In the NBA finals, the away team won five of the six games. In the NHL finals, five of the seven games went to the visitors. This year in the NFL, the home team has won just 53% of games, with 100 home wins and 90 away wins.

Soccer has a similar tale to tell. Here, I managed to find some historical comparisons. In the last thirty years, home wins in the premier league have declined on average from about 52% to about 42%. Thirty years ago, a home win was about 25% more likely than an away win, but now it is less than 10% more likely. A hundred years ago, home teams won over 65% of games.

It is not too difficult to identify several possible causes for the collapse of home field advantage. Many of the reasons that home advantage used to be significant have been offset in one way or another.

Playing at home was traditionally an advantage for a number of reasons. One was a home crowd that could gee up the home team while intimidating the away team. This can be intensely practical: in the NFL, a home team will enjoy a silent stadium when on offence, allowing for voice signals, but the crowd makes a din while the away team is on offence to make such signals impossible.

Then there are peculiarities of the venue. Even in soccer, where the pitch dimensions are rather uniform, Lee Dixon claimed it helped to know exactly where he was on the pitch by such things as advertising hoardings. In baseball, the field itself has strange dimensions and odd corners that must favour those familiar with it. It is more extreme in cricket, in which the home team actually prepares the pitch to suit their own team. I remember a game in the 1970’s when England prepared a pitch for Derek Underwood that was so biased that the opposition declared on 130-9. That is another lazy assumption – that the English are fair players.

Then there is preparation. In the NFL, it is always claimed to be a disadvantage to west coast teams to play one o’clock games on the east coast, effectively ten in the morning for their bodies, after a long flight. The travel itself takes up a chunk of possible training time. It is noticeable that home teams tend to win NFL games played on Thursdays, when the ratio of preparation time between the two teams would be most extreme.

Travel carries other risks. Players might not be so disciplined. Sleeping in a strange bed is always tougher for the first night. And then there is skulduggery. It wasn’t long ago that most of an England rugby team mysteriously acquired food poisoning just before playing South Africa away in a world cup game, and hotel fire alarms have a weird tendency of waking up visitors in the middle of the night.

Examining all of these partial causes of home advantage in turn, it is possible to see how that advantage has eroded over time. Most important is money and conditioning. Nowadays, teams have the resources to travel in style and stay in luxury facilities. Training and conditioning routines have matured so that teams can be made ready to produce peak performance at the time of the match. Regulations are better, skulduggery is harder, and pitch conditions are better and more uniform. Home advantage may have flipped, because trainers and medical staff can keep closer tabs on their players when on the road.

The crowd is still partisan, but not as it once was. At English soccer games, the away fans are often the most vocal, while many of the home supporters are either silent, or absent in the hospitality areas, or actively barracking their own team. How anybody can play well in Chicago, New York or Philadelphia escapes me, and indeed those cities often get the teams they deserve.

There is a tactical element as well. In soccer, attacking used to be more productive a strategy, and the home team is still expected to commit more players forwards. But for many teams now playing without the ball has become the most effective way to win. Leicester were brilliant trail blazers for this strategy when they won the league despite having the least possession in the whole division. They just soaked up pressure with men behind the ball and counter-attacked at pace when the opportunity arose. Most teams play a variety of this strategy now, but at home their fans expect more aggression.

As a result, playing at home can be a positive disadvantage, especially when teams are struggling. My own team, West ham, have been in a terrible slump, and it did not surprise me that the rare good result recently came in an away game against a good team, when they did not try to dominate possession. Being away also took pressure of players who had been sensing the intolerance of fans at home.

This all explains why home field advantage has been eroded. It also explains the situations where it is still strongest, for example midweek NFL games, or games very long distance travel to places with poor facilities like Russia (and also that teams often struggle in the games in short weeks immediately after such ventures). Home advantage still also persists when there is less money sloshing about and in less mature sports and events – it did not surprise me that Spain won the recent tennis Davis Cup at home, helped by a new tournament format with lots of quirks.

I find the persistence among pundits in failing to recognise a changing world instructive, because the same tendency exists elsewhere. We are often slow to recognise changing circumstances and too slow to challenge our assumptions. In soccer, the mantra of possession took the glaring counter example of Leicester to influence coaches. The power of statistics in baseball only became accepted once Oakland and others had demonstrated its effectiveness – this trend still has further to run.

What about outside of sports? Nobody expected the right wing of politics to move from the rich to the poor until Donald Trump and others came along, and in the current UK election old assumptions still colour commentary and even party tactics. An impeachment trial of public opinion was expected to move in decisive bands and based on facts, but nowadays everybody gets their news from their own bubble so new tactics are required.

In business, I believe that the advantages of scale have shifted. Scale used to be about production and distribution efficiency, but that has no value in most service industries, while network effects of communication and customer habit have become important. In most management situations, I believe scale is a positive disadvantage, since it works against agility.

What about warfare? The US always seems to be one war late when it comes to tactics. Last week’s Economist essentially torpedoed the value proposition of Aircraft Carriers, but still most powers want to build them, rather than spend somewhere more effective.

Assumptions die slowly, and we can all benefit from challenging the assumptions in our lives, whether we are a sports coach or a politician or just somebody trying to be a better parent. A good way to start a challenge is identify what factors cause an assumption to be true or false, and then examine trends that might influence those factors.              

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