Football is one of the most popular sports on which to bet, both in the UK and globally. When it comes to which markets are the most popular most people keep it pretty simple; backing one side or the other to win a given match remains the most commonly placed bet.
Going further still, within this market backing the home team is often the way many punters opt to go, in part because of the belief that being at home confers a strong advantage and, therefore, makes the hosts more likely to win.
Of course, whether the home team would be good value is another question altogether but for now let us consider solely the concept of whether or not the home team does indeed have an advantage. Does home team advantage exist in football, and if so how important is it? How big a factor is it in determining the score and, if it indeed is, why is this the case?
Home Team Advantage is Real
The first question – does the home team even have an advantage? – is a very easy one to answer: yes they do. Our focus here is solely on football but home field advantage, as it is called in some US sports, exists in just about every sport where opposing teams (or even individuals) play each other at partisan venues.
We can see home “court” advantage in basketball. In Davis Cup matches in tennis, the team playing in their own nation has a greater chance of winning and we also see the same effect in golf, for example in the Ryder Cup. Cricket, rugby and, as we said, just about any sport you care to mention, including athletics and the many other disciplines of the Olympic Games, are no different.
The reasons why this is the case may vary from sport to sport, although some, chiefly the support of fans, is pretty much common to all. One incredibly simple way to prove being at home is an advantage when it comes to football (and this can be applied to many other sports too) is to compare the home and away results of all the teams in a given league.
If we look at the 2018-19 Premier League results we can see how many points each side won both home and away:
|West Ham Utd
The table above shows us that 19 of the 20 Premier League teams accrued more points in front of their own fans than they did on the road. That is a strong and statistically important correlation and one that we are confident would be repeated in most leagues, in most seasons, in most countries.
Whilst Crystal Palace secured 20 points at home and 29 on their travels (almost certainly due to their counterattacking style being better suited to playing away), Fulham garnered 81% of their points at home. Everton took 63% of their tally at Goodison Park, winning 14 points more at home than they did away. Arsenal had an even bigger points differential between their games at home and those away, taking 20 more at the Emirates than they did on their travels.
That meant they won more than 64% of their points in front of their own fans and fewer than 36% when not at the Emirates. Looked at another way, the 45 points collected at home is 80% more than the 25 they managed away.
If home advantage did not exist at all we would expect sides to win around 50% of their points total at home and around 50% away. Of course, there would be some variation among the 20 Premier League teams but as the table above shows, only Leicester (with a 52%/48% split) come close to that.
Moreover, we would expect to see around 10 teams earning more points on their travels and 10 earning fewer. As said, 19 out of the 20 top flight clubs were more productive on home soil and so the stats undeniably prove that playing at home confers a strong advantage.
Looking at the picture across a longer period and including all four of the top tiers of English football reinforces this argument. A somewhat misleadingly titled feature article, “Sky Sports bust common football myths” looked into the issue.
Whilst home teams won almost 65% of games at the end of the 19th century, the article’s claim that “home win percentage hit an all-time record low in 2015-16 – crashing to just 41.0 per cent across all four tiers from 2,036 games” does not in any real way bust the “myth” of home advantage.
They go on to say of the 2015-16 campaign that “away win percentage hit an all-time high at 31.5 per cent” and that “the value of home advantage plummeted more than 36.0 per cent, proportionately, between 1895 and 2016.” All that is true, but even based on those cherry-picked stats looking at the single season in more than 100 years where they most suited the argument the piece was trying to support, sides were still 30% more likely (proportionately) to win in front of their own fans than in a hostile environment.
The article noted that home wins “bounced back to 45.0 per cent last season” (2016-17) whilst our own analysis shows that in 2018-19 it was up to 48%. The away team won less than 34% of the time so we struggle to see how Sky can really claim to have busted any myths!
How Powerful is Home Team Advantage?
So, if we accept that the side playing at home definitely has the upper hand, can we quantify by how much? There are many ways we could seek to do this, including looking at the stats that we have done above.
Jim Albert and Ruud H. Koning’s excellent tome, Statistical Thinking in Sports, looked at around 9,000 internationals from 1993 to 2004. They showed that 50% of the time the home side would win, whilst they would lose just 25% of their games.
Based on that we could say that home advantage makes a team twice as likely to win. Whatever method we use, of course, the numbers will vary depending on which league we look at and in what time period, as we have seen with Sky’s info above.
However, the bigger issue with only looking at the proportion of games won by the home and away sides is that it is rather a blunt tool. It is a statistical average that may only be of limited use in the more specific scenario of a given game you are looking at and seeking to bet on. Does a friendly international from 1996 between two South American teams really have that much to tell us about a crucial relegation six-pointer between, say, Newcastle and Brighton?
Whilst such general and overarching stats may well be of some use, we would suggest that refining them as much as possible would be wise. So, for example, trying to factor in just results from the relevant league over a shorter period, perhaps the last five years, may offer a more accurate indication. What’s more, looking only at the teams in question will certainly give you a better clue as to where the value lies from a betting perspective, especially if one happens to be especially strong at home whilst the other travels poorly.
Win percentages are rather a blunt tool in other ways too, essentially delivering a binary (win or lose) or at best ternary (win, lose or draw) answer. This may be of use for someone simply wanting to bet on the match odds but there are many more markets of relevance that it does not help with. These include betting on the correct score, handicaps, and Asian handicaps to name just three. Is there another way of assessing just how much home team advantage affects a game that might be of help here? And one that also gives a more nuanced answer that may be of assistance when it comes to assessing whether the match odds themselves offer any value?
How Many Goals is Being at Home Worth?
Well, there is, and that is trying to ascertain how many goals, or what portion of a goal, being at home is worth. If we have two teams of exactly equal ability and form and the only differentiating factor is that one plays at home and one plays away, what handicap would we assign to the home team to level the playing field?
Of course, in the real world, fractions of goals do not exist but when considering home team advantage we are looking at a theoretical average, so we might say that being at home is worth 0.4 goals to the home side, for example. We can calculate this in a similar way to win percentage by simply looking at how many teams are scored by the home team and how many by the away.
As before, if there was no benefit to playing at home, we would expect on average the home and away sides to score the same number of goals. However, this isn’t the case and as with winning more games the home side scores more goals, a correlation that is replicated in just about all leagues in all countries.
Once again, the home advantage in terms of goals varies over time and from league to league but if we consider the Premier League’s first 25 years, from 1992-93 to 2016-17, we can see that being at home is indeed worth around 0.4 goals per game. In the period specified the home teams have registered an average of 1.53 goals per game with the visitors scoring 1.12.
Seasonal divergence from those averages has been fairly minimal in the Premier League, with home goals broadly staying within a range of 1.4-1.7 and away between 1-1.22. You can make these stats more specific by only looking at individual teams.
So, for example, if we look at Man City in the 2018-19 campaign we can see that at home Pep’s side scored 57 and conceded 12 in their 19 matches at the Etihad. That’s an advantage of 2.37 goals per game. Lower down the table, Everton scored 30 and conceded 21 for an average of 0.47, whilst relegated Huddersfield scored just 10 but conceded 31.
Does that mean Huddersfield were worse off at home, given their average goals per game was negative 1.11? Well, no, because if we look at their performance on the road we can see their average was 1.74! So we might say that being at home was worth 0.63 goals per game to the Terriers.
As with all stats, there are many ways of using them and valuing them. How you choose to interpret these numbers is up to you but one thing cannot be questioned: home advantage is real.
What Factors Affect Home Team Advantage?
Given we have established that being at home is of value and improves the results of a team, asking why that is the case is the obvious next question. In answering this we might also uncover ways in which we can further refine any assessment of what home advantage is worth in a specific instance.
There are a number of factors that create the home team’s “head start” and the most important, in no particular order, are:
- Decisions of officials
Some of these are interrelated and some are multifaceted, whilst something that might appear to be a positive could actually be a negative. Fans are probably at the heart of home team advantage, which explains why lots of stats show it is greatly diminished when games are played behind closed doors, as happened at the end of the 2019-20 campaign due to coronavirus.
Supporters encourage players and can energise them, whilst at the same time they can influence the referee into favouring the hosts. This latter point may well be diminished somewhat due to the advent of VAR but it still exists. Premier League research prior to VAR being introduced showed that 63% of penalties were awarded to the home team whilst other research indicated that home advantage went up by 0.1 goals for every 10,000 fans inside the stadium.
However, fans can sometimes bring added pressure, or create a hostile environment that inhibits players, especially when things are going badly. Moreover, as we spoke about in relation to Crystal Palace’s record, some sides may prosper away from home if it better suits their tactics and style of play.
We have said that home advantage may have reduced somewhat over the years and one possible explanation for that is improved travel. In the 1800s away games might mean tough, time- and energy-sapping journeys. In contrast modern players travel in extreme comfort at far greater speed, sometimes flying when it is deemed beneficial. That said, it seems almost certain that travel remains a negative factor in team performance and there is research showing that longer journeys have a bigger impact than very short ones.
As well as not having to travel, when players are at home they have the benefit of familiarity. This can have an impact in a range of ways, including feeling psychologically secure and safe, to more obvious factors such as being comfortable with the dimensions and preparation of the pitch and even being able to control these to suit a team’s strengths.
Any punter who is serious about their betting should try to take into account as much information as possible, considering all of these angles. Home advantage is real and an average of somewhere close to 0.5 goals is accurate in general. However, dedicated punters can look at a huge range of stats and influencing factors in an attempt to evaluate what home advantage is worth in any given situation and may just get an edge over the bookies if they do.