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Friday, 9 December 2011

Trailing Teams Show More Attacking Intent in the EPL.

 Ask any casual football fan to describe the atmosphere at the Britannia Stadium,home of Stoke City and the likely impression you'll get is one of a constant cacophony of noise,capable of intimidating even the most hardened of visitors.This view is repeated and reinforced on Match of the Day whenever Stoke turn over a bigger club (usually Arsenal) at home.The Brit is not a place opponents enjoy visiting,but for more regular visitors to Stoke the truth is rather more complex.True there have been occasions when the Brit has literally rocked,a 1-0 win over Man City achieved with ten men for the majority of the match springs to mind as does any visit from City's neighbours United who are still considered,slightly perversely by many older Stoke fans as Stoke's natural rivals.But as with any natural organic process the Britannia crowd ebbs and flows and the decibel levels can sometimes barely register for considerable portions of a match.

The Britannia Stadium,an inhospitable place for opponents....on average.
A much more reliable constant is the physical experience of watching football during the winter months at Stoke.Perched on an exposed outcrop overlooking the highrise concrete of Stoke itself to the north and the more pastoral greenery of Trentham to the west,the ground is landmarked by a massive incinerator chimney,thoughtful positioned upwind to the prevailing gales.Two of the ground's diagonal corners have yet to be filled in resulting in the wind and rain funnelling itself through the ground virtually from November to March.Watching Stoke at home is a very cold experience.

However,despite the freezing night time temperatures few fans were feeling the cold as the left the ground after a 1-1 draw with Dynamo Kyiv.The Stoke fans had a warm glow that came from sealing post Christmas Europa League knockout football and the Ukrainian visitors who,used to much more severe weather had dispensed with a fair proportion of their clothing pre game.Combined with last season's FA Cup final appearance,it was a fine achievement for a team who in the nineties had vied briefly for the title of worst FA Cup team of all time.But the evening itself contained another paradox.

Pre kickoff,the game had shaken down into two possible outcomes.A Kyiv win would likely see them progress at Stoke's expense,while any other result would see the Potters progress.For around 70% of the first half the game had been all square and Stoke had been the team to progress,yet despite this comfortable state of affairs,the Potters had played abysmally.It was only when Kyiv scored and Stoke faced elimination that the home side started to play rather well,culminating in a late equaliser.Just like the famous Stoke atmosphere,the overall outcome was the sum of a couple of diverse extremes.

Rewind to Stoke's first season back in the EPL.Arsenal had been dispatched at the Britannia and Liverpool had escaped with a draw,but the other two of the big four would prove to be a harder nut to crack.A resilient rearguard action in the face of a largely ineffectual Chelsea side at Stamford Bridge was rewarded with a scrappy Delap goal,but having held the London side at bay for an hour the Potters then succumbed to two late goals in the 30 remaining minutes.

Taken in isolation these events are mere anecdotes,but they do imply that there is perhaps some mileage in the widely held belief that teams(and fans for that matter) are able to tailor their effort to suit the game situation.If you wander in on any televised game,mid match,the two things you immediately want to know is who's playing and who's winning (if indeed anyone is).The first question helps you decide the likely winner,the second the likely course the remainder of the game will take.So does the data point to teams being more likely to score when they trail than they were if for instance they were ahead.There certainly seems to be an instantaneous added urgency to a team's efforts once they draw to within a goal of their opponents,witness the common sight of the scorer rushing into the net to retrieve the ball and carry it back to the halfway line.

To help answer this question we first need a baseline to describe what happens to a team's scoring abilities on average.We saw here that the chances of a team scoring the first goal in a game is directly proportional to the amount of goals that team can expect to score on average in that match up.The good news is that what holds true for the first goal is also on average true for any subsequent goals.In addition the rate at which both teams scoring abilities decays with time throughout a game maintains the expected scoring ratio for both teams.In short if you've a 60% chance of scoring the first goal in a game,then you've a 60% chance of scoring the 2nd or 3rd goal.....on average.

However,if we look at the numbers for the EPL over the last half dozens seasons we see that there is a consistent trend for the league teams underscoring the amount of expected goals when a team leads and overscoring their expected amount when they trail.I'll illustrate this with examples from the last 5 seasons using data from two polar and opposites both in talent and alphabetically from the EPL,namely Arsenal and Wigan.

Wigan have consistently struggled over the last couple of seasons,they currently lie bottom and escaped relegation with a last day,78th minute winner at Stoke.So unsurprisingly,on average they aren't usually the favoured team in a match up and by my estimations they were expected to score around 38% of the goals in games over the last five seasons where they trailed at any stage by exactly one goal.Therefore,they'll have around a 38% chance on average of scoring the next goal in those games if the situation of Wigan trailing has no effect on their ability/desire/effort made to score next.However,as the table below shows,when trailing by a goal,Wigan mimicked the league trend and managed to haul themselves up to a scoring rate of 43%.

 Wigan's Scoring Rate when trailing by 1 goal compared to their seasonal average.2007-2011.

Seasons. No.of Times
Wigan Score Next when Trailing by 1
No. of
Times Opponents Score Next when Wigan Trail by 1.
Wigan's Average Pre
Game Goals Expectancy.
Opponent's Average
Pre Game Goals Expectancy.
2007-2011 32 42 1.01 1.67
% of
 Next Goals Scored/Expected to be Scored.
43% 57% 38% 62%


Wigan's Scoring Rate when Leading by 1 goal compared to their seasonal average.2007-2011.

Seasons. No.of Times
Wigan Score Next when Winning by 1
No. of
Times Opponents Score Next when Wigan Lead by 1.
Wigan's Average Pre
Game Goals Expectancy.
Opponent's Average
Pre Game Goals Expectancy.
2007-2011 18 34 1.12 1.44
% of
 Next Goals Scored/Expected to be Scored.
35% 65% 44% 56%


By contrast the reverse is seen when Wigan led by a goal.This time in games where Wigan took a lead of a goal they were expected to score 44% of the next goals,(they generally lead against poorer teams than they trailed to),but this time they scored just 35% of the next strikes.Or to put things another way,teams trailing by a goal to Wigan were more likely to score next than their per game seasonal average expectation would have suggested they were.

Wigan,more likely to be seen on the defensive if they lead the game?

  The case of Arsenal is identical,over the same period they would have been expected under scoreline neutral conditions to score 64% of the next goals in games where they at some time trailed by a goal,but they actually scored 69% of the time.And when they led their ability to score next dropped from an expected seasonal average for games of that type from 72% to an actual 70%.

In short teams who lead become slightly less likely to score next and trailing teams become slightly more likely.Over seasons and sometimes even within individual games this effect tends to cancel out,but within the context of a single game the effect can be a significant component that goes towards explaining the dynamics of the match.The reasons for this universal phenomena are likely to be much more complex.Teams are likely to be pacing their effort to stretch for the full ninety minutes,even in an era of increased fitness and three substitutions,so an immediate,reckless all out assault shouldn't be the expected response from a team falling behind.More common,time permitting,will be a gradual cranking up and re balancing of attacking intent and defensive risk.Similarly,a one goal lead can make a more cautious approach very enticing.

At least if your team is losing you can expect to see them showcasing their attacking abilities to best effect.

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