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2011/12 EPL Season Review--Possession Part 3e (expected shots on target against)

Welcome one and all to part 19 of the never ending 2011/12 season review. I have looked at four different measures so far and I have only three remaining. In the last post we looked at shots on target for. The logical next step is to look at shots on target against/conceded.

Join me after the jump for explanations, wizardry, and colourful graphs. Get ready to concentrate.

A quick explanation is needed for how we work out what each teams expected shots on target against total was.

Average EPL possession over the seasons course 50%

Total shots against in the EPL 2011/12 3534

Average per team 176.7

Average per 1% of possession 3.53 (176.7/50)

Arsenal as an example- 131 shots on target against, 3.17 shots per 1% of Arsenals possession (58.76%).

Actual shots on target against per 1% of possession was 3.17 vs 3.53 expected shots on target conceded per 1%.

To get that figure we use Arsenal's shots on target against total/possession conceded (41.24)= 3.17 per 1% of possession.

Expected shots against is a teams possession% x 3.53 (the League's average shots per 1% of possession)

Shots On target Against With Possession

Sota_with_poss_medium

This is the raw data showing shots on target against along with possession for, which decreases left to right.

Notice the more possession a team has the greater the likelihood of the shots on target against number being south of the mean line. Is possession more about preventing chances than creating your own?

Shots On Target Against Per Teams 1% of Possession

Sota_per_perc_medium

Here is each individual EPL teams shots on target against per 1% of the oppositions possession number, calculated using the 38 game possession and shots on target against numbers.

We use the oppositions possession number as we are trying to discover each teams ability to stop the opposition from getting a shot on target (shots on target against).

Shots On Target Against Per 1% of Opposition possession (differential)

Actual shots on target against vs expected shots on target against

Sota_per_perc_diff_medium

Here we see each teams actual shots on target conceded versus the expected shots on target conceded number.

So there isn't a great deal that leaps out at us here. On the plus side of the mean we have Everton who conceded 1.08 less shots per 1% of possession conceded than was to be expected. This is a very good number considering what the number that the clubs at the left hand side of the chart posted.

Liverpool are second, another excellent statistic count for them. Stoke are third with 0.55.

Man United, who are below the mean line again in terms of shots or shots on target against, post a -0.18 per 1% conceded number. A high goalkeeping save % was the reason these numbers didn't sting too much.

Swansea, poor again. Bolton are worse. Wolves are atrocious.

Actual Shots On Target Against vs Expected Shots On Target Against

Sota_act_v_exp_medium

Here is the Actual versus expected. For a clearer view.

Actual Shots On Target Against vs Expected Shots On Target Against (+/- differential)

Sota_exp_v_act_diff_medium

This is the graph that we are really interested in as it shows the +/- number for the whole season.

Thoughts

Everton are great by this measure, 57 shots less on target than was expected means so much to a club like Everton and is probably the difference of a couple of EPL place when all is told. EPL scoring % is 3 goals for every 10 shots on target. The math is simple, Everton saved themselves from a lot of goals conceded with this excellent +/- number.

Stoke are strong by this method, too. 33 shots on target less than was expected of their individual possession number. This is the one stat that saved their EPL skin as by most other statistical measure they were a bottom 4 EPL team.

We see a little wrinkle where by the 5 worst teams by possession all post a better shots on target against number than was to be expected. Why? I'm not sure, it seems like some kind of survival mechanism. The surrendering of possession and territory in order not to expose themselves to attacks from the better quality players from the opposition.

Actual Shots On Target Against vs Expected Shots On Target Against (+/- differential per game)

Sota_diff_per_game_medium

Here is the previous chart but changed to +/- per game.

Wolves are really poor here, 2.33 shots worse than expectancy. Swansea fare no better and with them we see more proof of their mirage of excellent possession.

Man Utd have a negative number but the size, or lack thereof renders it harmless. Bolton and Norwich are on the cusp of having really harmful - shots on target against numbers, well in Bolton's case it was.

A word for Blackburn here. Relegated, laughed at, under siege from their own fans yet they posted decent numbers in a few of the categories we have looked at in this series. Sots on target against is yet another one. They outperformed expectancy yet they conceded 78 goals in the 38 game schedule. Why? Save %, Paul Robinson and maybe the effect of shot quality, which is a complex thing to prove.

Everton are the real winners and for once I praise Stoke. Credit where it's due, these numbers saved their season.

Next up

  • Goals for and against

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