Blackburn 2-3 Liverpool.

Blackburn's heady mix of ragged defending and potent goalscoring continues to delight the neutral and frustrate their fans as they attempt to keep their heads above the drop line.Around 70% of their games have featured at least three goals,with 3-3's and 4-3's relatively common place.3-2 was the weapon of choice when they overturned the champions elect at Old Trafford and when they defeated fellow strugglers,QPR,but this time they were on the wrong end of the scoreline.

A pulsating game saw each team's Expected Points peak and trough throughout the evening.None more so than in the 25th minute.An early 2-0 lead to Liverpool on the back of Rodriguez's brace had seen the host's EP fall to just over 0.1 of a point,but the penalty award alone bumped it up to nearly 0.4 and upwards again to almost 1.0 as the red card quickly followed.But it settled back down to 0.5 points when Yakubu's tame penalty went unconverted.

The prolonged time spent playing a man down finally cost Liverpool their lead when Yakubu added to his first half header with yet another penalty and the hosts spent the rest of regulation as the team favoured to take most points longterm.That is until Carroll's injury time header sealed a welcome win for the visitors ahead of Saturday's FA Cup semi final derby game.


Scorers.
0-1,Rodriguez,13'
0-2,Rodriguez,16'
0-2,Penalty awarded to Blackburn,25'
0-2,Doni Red Card,25'
0-2,Yakubu missed penalty,27'
1-2,Yakubu,36'
1-2,Penalty awarded to Blackburn,61'
2-2,Yakubu(pen),61'
2-3,Carroll,90+1'

Manchester United Get Their Just Deserts at Old Trafford.

The Patrick Vieira row over referees appearing to favour big,well resourced teams who originate from Manchester and are fighting for the Premiership title when deciding  whether or not to award penalties continues to rumble on.We've shown here that both sides from across the blue and red divide can benefit from the occasional lapse in refereeing concentration,but also that over the stretch the better teams do more attacking and therefore get the lion's share of the attacking spoils.For once Graham Poll also put one and one together and came to the same,almost certainly correct conclusion that better sides get more goals,more corners,more shots and more penalties.

To be fair to Vieira he did qualify his remarks by singling out Old Trafford as a venue where opponents find penalty decisions difficult to get,so instead of looking at both home and away matches,I've concentrated solely on home games.We saw previously that if Premiership sides scored say 60% of the goals that were registered in their matches,they could expect to gain a very similar proportion of the penalties awarded in those same games.And the following graph paints a very similar picture if we look at only a team's home games.

 I've looked at the last six season including the present one and although the correlation isn't quite as tight because I've used slightly fewer teams and games,the previous trend is still present.The proportion of penalties you are awarded at home is intimately connected to the proportion of goals you score at home and for much of this sample it is a one to one relationship as before.If you get half your game's goals you should expect to get around half of the penalties that are awarded. Manchester United at Old Trafford scored 80% of the goals over the period I looked at and they received 73% of the penalties,sample size caveats apply,but you could decide that there's the possibility that they were actually short changed.Or maybe the referees invoked their own mercy rule in games where United were romping to victory.

A penalty that is given for a simple trip in the box with little immediate threat being exerted towards the goal is often difficult to take if your side is on the receiving end.But the decision is no different to the steady accumulation of free kicks that happen as a superior side launches wave upon wave of attacks and no side at present is superior to the likes of Manchester United and City,especially on their own turf.So it is very likely the bulk of the penalties will go to these sides when they play at home.Some visitors to Old Trafford even manage to concede two penalties in 15 minutes,Stoke for example back in January.

Vieira's complaint arose from a penalty that wasn't given,but the relationship that exists between United's goal scoring ability and their penalty acquiring talent obviously also applies in reverse to United's defence.They allowed only 20% of all the total goals scored in matches at home and so they would expect to concede about 20% of the spot kicks that were awarded.So the award of a spot kick to United's visitors should be a relatively rare event,four United penalties to every one for the visitors and it's scarcity shouldn't be a sign of anything sinister.No doubt Fulham were disgruntled because of the spot kick they didn't get on Monday.But basing a conspiracy theory on an isolated incident at the tail end of a season ignores the bigger picture.One contentious decision is simply an anecdote.

Vieira goes on to say that the same bias occurs in both Spain and Italy,but again the figures say not.As the following two graphs illustrate the same type of relationship between attacking endeavour and reward exists in both Serie A and La Liga.

These graphs don't differentiate between venue,but are identical in form to the plot for the EPL indicating that it is very likely that attacking intent on the continent reaps a long term penalty kick reward and miserly defences largely avoid conceding spot kicks.

Time of Possession in the EPL.

Time of Possession is fast becoming one of the hot topics in the world of football stats and such is it's current pre eminence that it has become almost the number by which a team is judged.Barca of course are the darlings of ToP and such teams as Arsenal and Swansea are praised for their accurate passing style that also boosts their time in charge of the ball.Mystification along with a faint hint of disgruntlement accompanies any example of a side who win the game's ToP,yet fail to win the game.Hopefully this post will make a convincing argument as to why you should expect a significant proportion of ToP winning teams to actually lose the individual game and why game long ToP shouldn't even be considered as a "real" stat.

Teams use possession for a variety of reasons,some defensive and some attacking in nature.The temptation to stereotype teams on the basis of one particular trait should be resisted,but it's hard not to see Barca and Swansea as polar opposites in possession terms.The former use possession and a host of world class attacking players to score goals,whereas The Jacks use it to prevent their opponents from scoring.Swansea held scoreless the first four EPL teams to visit The Liberty,picking up 8 points in the process and almost 40% of their games has seen their goal remain intact.Tellingly,they have also failed to score themselves in a similar percentage of matches.

On average most other teams use possession in a way that doesn't emphasis extremes of attacking or defensive philosophies and in addition current score can influence how teams accrue or cede the ball.A side who hold a comfortable lead may add to their possession statistics by passing the ball around in less congested areas such as defence or another may happily defend in depth and in numbers,but in doing so concede possession.In short the ways in which a team can decide to try to increase or reduce their time on the ball is dependent upon game situation,are numerous and often depend upon team tactics and there in lies the fatal flaw of trying to interpret ToP.

It is a secondary statistic that has been derived from a composite of many other primary stats that are fundamental to a team's success,often opposing in nature and quite often related to the talent pool of individual sides.Teams get possession by being good at making tackles or interceptions,they keep it by passing well,they use possession to create chances,they score goals by converting chances and they win games by scoring more goals that they allow.So we have a chain with match result at one end time of possession at the other,but in between are statistics that are ability based,context dependent and often better indicators of match success.

ToP is an amalgam of other more informative numbers,so why look at ToP when you can look at the components that go towards defining it.

If we use shot per game allowed and conceded as an example of a fundamental football statistic,we can show why this is a much more powerful measurement of a team's ability than time of possession even though we can use both to come to very similar conclusions about a team's ability.It's reasonable to assume that for the vast majority of teams,increased possession will lead to more goal attempts by that team and less from their opponents and this appears to hold true over a 38 game season.As we can see,the differential between attempted shots and shots allowed becomes positive and increases in size as possession passes 50%.

If we now chart a team's seasonal success rate,that is it's number of wins plus half it's number of draws all divided by it's number of games against average shot differential over the season we can see that the correlation is both strong and in the expected direction.Each data point represents one team's season consisting of 38 games,or 31 for the present year.

Team possessions plotted against success rate produces a similar graph,although the correlation is not quite as strong.The similarity isn't a surprise as we have speculated that one of the aims of a team while in possession is likely to be shot creation for itself and prevention for the opposition.

So if we now use both of these graphs to work through a real life example we can demonstrate the different levels of information we can deduce from a derived stat such as ToP and a talent based one such as shots per game.In 2010-11 Newcastle's average ToP was virtually 50% and it's shot per game differential was zero.So on average they kept the ball for as long as their opponents and on average they attempted as many shots as they allowed.From each of the above graphs we therefore can predict that their success rate for the season would have been 0.5.However,it was only 0.46.

Now if we came to our conclusion that Newcastle's actual results under estimated their probable ability based on historical results from the shots per game model,we can look back at their 2010-11 matches to see if they were short changed by short term luck during the season.And we find that their success rate in games where they were out shot by their opponents was 0.37.They were outshot on average by 9 shots per game to 14,comprising 20 games and based on the season long graph we can possibly say that they very slightly overperformed in those 20 matches.In the remaining 18 games,Newcastle out shot their rivals by 14 shots to 8 and their success rate was 0.55.An improvement compared to when they lost the shots per game duel,but probably well below what an average team would expect with such a record.Indeed if we look at individual games,Newcastle managed to lose five games where they outshot the other teams.A quarter of such contests.

We can explain such situations were a team has more shots,but loses the game thus.Teams will have an historical average rate at which they turn shots into shots on target and ultimately goals.On a particular matchday these rates will fluctuate around their historical means because one game represents a very small sample size,especially in a low scoring sport,such as football.It's therefore to be expected that the vagaries of short term luck will in a season's worth of games see some teams being overly unfortunate in the number of games where they have more shots in a single game,but end up scoring less of the goals.That may have contributed to Newcastle's lower than expected success rate based on their shots per game stats.

By using ToP we can also deduce that the Toon should have had more wins or less losses in 2010-11,but we have no way of knowing which factors may have contributed to the short fall.Even if we isolate games where they dominated possession and lost,we still don't know if they shot inefficiently,played Swansea style keep ball and succumbed to a late goal or just made individual errors.ToP tells us nothing that other fundamental game stats won't tell us with more illumination.

If we can put ToP into context it may become a valuable addition,but in it's present catch all,game long form it struggles to compete.

for more great thoughts on time of possession,check out 11tegen11 and 5 AddedMinutes.