Return of the E Ratings: League 2: 21 Jan 2018
Quick intro / recap
At the start of the season I mentioned that there would be a bit of a delay in getting the E Ratings live again. There were two reasons behind this:
- The official data being collected for the National League, which had for years been at the same level as the EFL, was cut back significantly (presumably for cost reasons). To me this feels like a huge backward step that they’ll ultimately regret, but (that aside) it also broke the model, which needed that data to establish a starting rating for newly-promoted clubs from that division.
- I wanted to make the model better, having read a slew of interesting posts over the summer about approaches that could potentially improve it, so I took it to pieces and started to rebuild it from the ground up. However towards the end of the summer my team at work won some additional contracts that soaked up most of my free time, so I kept having to park it.
I’ve still not gotten around to addressing (2), which is a huge job and needs a stretch of unbroken time (and lots of testing) devoted to it, but I was starting to get sick of not having the ratings around so I’ve slapped the old model back together and come up with a quick fix for (1) – basically using actual goals instead of expected goals to feed the ratings – which will have to do for now.
Here is the latest update of the season to the E Ratings and how they predict the rest of the season will pan out. The rating system is explained here, but in a nutshell it’s based on the combined quality of chances that clubs create and allow, rather than their results.
The attack rating broadly equates to how many goals’ worth of chances a team would create against an average opponent (so higher is better), with the defence rating equivalent to the chances they’d be expected to allow (so lower is better). The overall rating is the difference between the two – effectively the average expected goal difference per match – so a positive number is good and a negative one is bad.
The graphic below lists each club in descending order of their overall E Rating and shows how this – along with their individual attack and defence ratings – has changed over the past 30 league matches. The red and green arrows indicate how the overall rankings have moved in the past month and the numbers in brackets show the ranks for each team’s attack and defence ratings.Luton‘s performances have been ebbing slightly of late but they’re still the best-looking side in the division overall. Wycombe‘s ratings are improving steadily and they actually look to be more or less the Hatters’ equal in attack, albeit less so in defence.
For Coventry and Lincoln it’s the attack that could potentially do with some improvement if they’re to sustain their promotion challenges: defensively both are already impressive.
Despite their big win over Cambridge, Forest Green need a few more positive performances to shake off the mantle of worst-rated team. Their ratings have levelled off recently and, along with those of Yeovil and Morecambe, could be on the up, while Barnet have been on a downward trajectory lately thanks mainly to their defence.
Predicting the rest of the season
Below I’ve used each club’s current ratings and those of their remaining opponents to predict how the rest of the season could play out. Each of the remaining fixtures has been simulated thousands of times, using the current E Ratings to generate probabilities for where each club will finish.
This graphic shows the cumulative probability of where each club could end up, in descending order of average points won. You can think of the ordering of the teams down the left hand side as a “best guess” of the final league table, with the coloured bars showing the relative likelihood of each club ending up in a certain section of the table:
Luton remain overwhelming favourites for promotion, with four clubs currently scrapping it out for the other two automatic slots. Accrington and Notts County appear likeliest to prevail at the moment, but Wycombe and Coventry aren’t far behind.
At the bottom, Forest Green and Barnet are currently out on their own as candidates for the drop, with both considered marginally likelier to be relegated than survive. There’s still plenty of time though, and a clutch of teams around them are still not out of the woods.