Why Bolton Wanderers are now giving themselves a chance with greater xG

Billy Crellin’s penalty save on Tuesday night against Bradford City kept the Bantams at bay in a second half where Wanderers rode their luck, but it’s luck they deserve for turning performances around after a sluggish start to the season.

There are still things to be worked on, that is to be expected after recruiting a whole new squad and trying to implement a demanding playing style. Ian Evatt’s men however now look much more likely to do that all important thing in football – score.

I’ll admit that I was worried after the first three games as to where exactly the goals would come from but things seem to be improving, with excursions into the final third now becoming more commonplace.

Fair warning: I will be touching on a statistic that some people may have not heard of before called ‘Expected Goals’.

For those not familiar with expected goals (xG) it is basically a measure of chance quality. Each shot has an ‘xG' between 0 and 1. What that means is, a shot with an xG of 0.1 has a 10 per cent chance of going in. For example, in the graphic below, a shot from three yards out has about an 80 per cent chance of being scored so it is given an xG of 0.8, i.e. a player would expect to score that chance 80 times out of 100.

A shot from outside the penalty area indicated in the position below has about a 5 per cent chance of being scored so it has an ‘xG’ value of 0.05, i.e. a player would expect to score that chance 5 times out of 100.

I appreciate that you may not have got your head around expected goals just by reading that – for a better explanation I’d urge you to watch this YouTube video.

The reason I’m giving an explanation of expected goals is because it is now widely accepted (in nerdy football stats circles at least) to be a good indicator of a team’s attacking performance.

Watching the games back it’s clear to me that the team now pose much more of a threat in the final third of the pitch.

Whilst this hasn’t led to a plethora of goals just yet, early signs are promising that this might just be the start of a more free-flowing, attacking Bolton Wanderers.

In the graph below I’ve plotted shots* in the penalty area for each game played so far (blue bars) along with the expected goals total for each game (orange line).

*I’ve stripped out headed attempts as I wanted to focus on quality chances that come from good attacking play rather than a header that skims off an attacker’s head after a long ball into the box.

The change after Grimsby is noticeable, with the team now creating more foot shots in the box coupled with an increase in expected goals as the season progresses. (If you are wondering what the orange dashed line is – I have cheekily included what the expected goals would have approximately been for Cambridge if Brockbank’s completely legitimate goal had counted).

You may not agree but I believe the tentative signs that the team turned a corner after the Grimsby game are there.

If we compare the shots taken against Forest Green, Newport, Colchester, Harrogate and Grimsby and compare them with the shots they took against Oldham, Barrow, Cambridge and Bradford the trend becomes yet more noticeable.

The graphic below on the left shows the shots Wanderers took in the penalty box in the first five games. The graphic on the right shows the shots Wanderers took in the penalty box in the subsequent four games.

The Whites managed to get 21 foot-shots away in the box in the first five games for an average of 4.2 per game. In the subsequent four games, they increased this to 23 shots for an average of 5.75 per game. More importantly the number of shots in the red ‘danger area’ has increased from one in the first five games to four over the last four games.

There’s still very much room for improvement – in a league table of shots in the box per game, Bolton currently sit 16th with 6.7, for context Carlisle and Harrogate are joint top with 10.1.

But the stats are backing up what we’re all seeing on the pitch. This is an improving team, who are starting to get it together.

*Data from whoscored.com

Follow Cameron on Twitter @analysis_bwfc