Wednesday 26 March 2014

Man United Season Comparison

United are obviously struggling this season but until recent homes defeats to Liverpool and City I've noticed a lot of people and media on the fence about where the Old Trafford club really stand this season. There have been some good results, at times, and the narrative has been Moyes must be a good manager, he's been unlucky, he's inherited a weakening squad from Ferguson, who himself got away with it last year. 

In the following two charts I've compared performances and results from the same games this season and last season. United's opposition are lined up approximately from best on the left to worst on the right so that you can easily see how United perform against the better sides compared to the worst. 

The colour of each bar is the result, won, drawn or lost. The height of the bar is my measure of performance using the 'expected goals' difference or xGD, this being the difference between volume and quality of chances created by each side. Based on historical results, an xGD of +0.5 makes a win 50% likely with a draw or loss at 25%. An xGD of +1.0 is 60% win, 25% draw, 15% loss. It's a linear relationship so think in reverse for negative xGD (e.g. -0.5 = 50% prob. of a loss).

Last Season

Starting on the left for United's toughest home games, from the same games played this season we can see they only dropped points in 3 fixtures and two of these were against closet rivals in City and Chelsea, the other Tottenham. In all three defeats United were only marginally outplayed based chances created and 'expected goals' difference (xGD). Possibly games they could have drawn or won on another day.

For their home wins, most were on the back of convincing displays with plenty of good chances created and few conceded. An element of good fortune/finishing/saves could certainly have been a factor in wins over Arsenal and West Ham.

Away from home, United looked outplayed by City but picked up the 3 points largely thanks to awesomeness from Van Persie. They did dominate most games against their closest rivals though, outplaying Liverpool, Chelsea and Arsenal and picking up 7 points in the process. Against the midtable sides, United failed to pick up what appears to be deserved wins against everybody except Spurs. Aside from a shock and undeserved defeat at Carrow Road, United beat all the lower table sides on the road but their performances look far from convincing against QPR, Fulham and Sunderland.

Overall I would not say United got lucky with an 89 point total last season. At home maybe they snuck a cheeky 4 points from the Arsenal and West Ham games. Away they looked to have dropped more points than gained based on xGD performance.

This Season

The home whuppings by Liverpool and City look very bad on Moyesie's United CV but only Chelsea can say they've stood up to these two this season. Last season's home performance against City isn't a million miles away from this season, plus Moyes can't be blamed for the form of Liverpool. How would a Ferguson-led United do against either of these two this season? City have beaten United 4-1 and 6-1 in past seasons.

United had the best of the chances in an early season clash with Chelsea although Mourinho set his side firmly for a 0-0. A convincing performance didn't yield any points against Everton and Martinez' guerilla football. Defeats against Spurs, Newcastle and WBA were in very close games that could have turned out differently on another day. Theses defeats are offset by victories against Arsenal and Stoke despite not bossing the chances. Liverpool and City aside, against the top teams United's performance hasn't been all that different from last season, although the results have.

Against the lower league sides United have been mostly dominant at home, and generally much more so than last season. The Fulham draw is definitely 2 points dropped.

Away from home United actually lead the league in points this season, as they did last year. This time around their performances look much less convincing though, rarely getting close to the +1.0 xGD mark and from a purely statistical point of view it would appear they've lucked into a few victories on the road.

It has to be said though they have had the majority of chances in most of their away games and their finishing has been excellent. I believe the likes of Rooney and Van Persie are definitely above average strikers, especially compared to what the bottom half of the table can put out. It's all very well creating chances, they still need to be finished,

Whilst they won close(ish) encounters away from home against lower to mid table clubs United have failed to get much out of similar close games against their main rivals. Van Persie missed a great chance to rescue a point early in the season at Liverpool. A 10 minute Eto'o hat-trick at Stamford Bridge, the first a looped deflection off Carrick, knocked the stuffing out of any chance of a result there..

One thing to note is that the profile or distribution of results and performance looks very different between this season and last. Under Fergie, United hit a steady and consistent level of performance over teams regardless of their standing in the league, whilst in Moyes' tenure performances and results are all over the place and a lot more skewed toward the weaker end of the league. 

This may be down to a trait I've been playing about with which I'll call 'Influence'. Does a team dictate the amount of chances in a match for both teams? Or does a team simply perform to their own level within the terms of their opposition?  For example, Liverpool and City look very influential, it doesn't matter if they go to the home of the most defensive team in the league, they'll still play and perform the way they want to. Similarly with Chelsea, but from a defensive standpoint. It doesn't matter who you are, you play Chelsea, they won't let you have many chances. United don't look influential at all this season. If they play good teams they get beat. If they play lesser teams they beat them. This was not the case last season where it was they who wrote the script.

This of course sounds pretty obvious but if can be measured from a team's numbers (possibly by correlating a teams' performances vs. opponents against what is expected against said opponent) then it may prove a useful indicator of a team ability on top of a 'raw power' metric like xGD. For example, maybe Chelsea, whilst not boasting such mighty goal/xG numbers, are more 'influential' than City right now?

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