Home Sweet Home.

Over the last couple of decades almost a third of the current Football League and Premiership clubs have upped sticks and left their previous homes for pastures new. Evocative names such as Saltergate, Layer Road, Leeds Road, The Goldstone Ground and The Victoria Ground have passed into history, to be replaced by more impersonal monikers such as The Ricoh Arena, The King Power (formerly the Walkers) Stadium, The Reebok, The Britannia and the imaginatively named Cardiff City Stadium.

Many of the bulldozed grounds had housed the local football team for generations and often the proposed move was met with a lukewarm response from many lifelong fans. Much improved facilities and the increasingly impractical locations of many original grounds meant that some of the early fan resistance has evaporated, but it is equally true that the new grounds needed time, coupled with some memorable results before they were fully accepted as home.

Home advantage is an almost constant feature of professional sports and is especially prevalent in team based sports. In football the home side's improved level of performance compared to their road game can be easily quantified. Although still a major component in driving the result of a sporting contest, home field advantage appears to be steadily declining in English football. Below I've plotted the average difference per game in goals scored by the hosts and those scored by the visitors combined for each of the four English leagues. Towards the end of the 80's a host side scored on average half a goal more than did their opponents, winning around 46% of such matches in the process. By last season, with an occasional blip such as 2009/10 HFA has shown a steady decline including a couple of season when it has dipped below three tenths of a goal.

Many theories exist to explain this constant feature of the footballing landscape. Crowd pressure may unduly influence the referee to favour the team with the most fans in the ground, almost always the home side. Studies have been carried out showing that incidents shown to referees with and without crowd noise results in different decision being made, but all of the refs in the study where amateurs from the Staffordshire FA. Hardly representative of a Premiership or Football league official. The constant decline over the last two decades would also appear to indicate that some factors are still evolving, with tactical formations being a likely and under investigated cause of the away side's increasing ability to compete.

The most widely accepted traditional reason for home field usually involves familiarity with your surroundings and a desire to protect territory increasing testosterone levels enabling the home side to enjoy a marginal advantage in the many individual contests which occur during a game, leading to an accumulated advantage at home compared to away fixtures. We can use the recent glut of relocations to try to test the familiarity claims.

A side beginning life in a new ground will be no more familiar with the surroundings than many of their opponents. Often the first opportunity a team will have to play on their new ground will be the opening league fixture and in the case of Stoke in 1997, The Potters had already played four away fixtures before their new ground was ready to host a match.

Summer 1997 & The Brit is well on the way to being just a few weeks late.

If home field advantage is partly driven by familiar surroundings, a team may sacrifice part of that advantage when they move homes and a decreased home premium may be present in the results. One season's worth of results for a single team may simply through a noisy sample throw up occasional home and away splits that aren't representative of larger samples. Home or away specialists can be seen every year in every division, but few if any retain the trait over larger numbers of trials. So instead of looking at the 27 individual cases where a side has played at a new ground I have aggregated all the cases.

We also need to account for the different home field environments in which each of the 27 individual seasons were played. Walsall left Fellows Park for The Bescot Stadium in 1990, when home English football sides were enjoying a home advantage of almost half a goal. In 2005/06 when Swansea moved to The Liberty it had fallen to around 0.35 of a goal.

                        How Levels of Home Field Advantage Change With A Change Of Ground.

Season.	Average HFA (in goals)  for Relocating Teams.	Weighted Average HFA for All Seasons.	Team HFA as a % of League Average.
3 Years Before Move.	0.40	0.40	100
2 Years Before Move.	0.40	0.40	100
Last Year In Old Ground.	0.50	0.41	122
First Year In New Ground.	0.34	0.39	88
Second Year In New Ground.	0.34	0.37	92
Third Year In New Ground.	0.37	0.39	95

Above I've charted the average HFA for all 27 sides in a couple of seasons prior to and post their move. I've compared this figure to the average weighted home field advantage for English football as a whole in the relevant years. In short a figure of 100% in the final column shows that the group of 27 were delivering the league average for home field advantage. Above 100 indicates they were enjoyed an enhanced HFA compared to the league as a whole and figures below 100 indicate a reduced comparable HFA.

The 27 teams were split fairly evenly across all four divisions, some were successful, while others celebrated their relocation by getting relegated just before their move. There was no reason to suppose that the group were consistently more proficient than usual at home (if such a species exists) and in the two years prior to their last season at their new home, the group produced dead eyed average HFA in each season.

In their final year they performed markedly better at home and while 27 completed seasons is a large sample size, I am reluctant to dive in and state that the players, fans and opponents are intent on giving the old ground a send off to remember. Of more interest is the dip in HFA that occurs in the first year at a new venue and only gradually recovers towards league expectations over successive seasons. Overall the 27 teams struggled to give the levels of home performance that their efforts on the road suggested they should have been capable of.

Some teams managed the transition effortlessly. Chesterfield had a great season at home, but Colchester struggled and overall more teams mirrored Colchester's experience, possibly indicating that home advantage had become more of a neutral experience that only improved with the passage of time.

A new ground gives the opportunity to examine results where one of the most cited causes of home advantage may be reduced. While competing and opposite factors may also be present after such ground hops, such as increased, if not always utilised extra capacity, there seems reasonable grounds to support the theory that familiarity breeds more points.