I did some updates to my interactive transfer evaluator – the stats are all the same (2014-2015 season stats) but I cleaned up some code and listed a few players under multiple positions to get it ready for the January window. I thought a good way to introduce it to my new followers was to show a demonstration with the EPL’s biggest story of the first half of the season: Jamie Vardy.
A quick discussion of the method behind the transfer evaluator: my model’s predictions are a function of player stats (aggregated to the team level) and a “team strength” coefficient. To evaluate how well a player would do on a new team, I remove the player currently in the position, subtracting his stats, and then substitute the new player, adding his stats. The model then recalculates the probabilities for all 38 games, adds the expected values up, and gives the new points. It’s a fun interactive app, and was a lot of fun to build so I’m pleased to see how much people have enjoyed it.1
So I wanted to test what my model thought of Jamie Vardy compared to the EPL’s elite strikers and on some Big ClubsTM. It found that many of these teams would have done well to sign Vardy last summer – the results are presented in the graph below.
Keep in mind all of this was done before this year happened. Vardy’s record-breaking goal streak isn’t included in this model, only the underlying stats from 2014-2015 (for strikers these are mostly shots, shots on target, shooting accuracy, and probably some passing stats). He’s an improvement over Wayne Rooney (+4 points for United), Christian Benteke (+3 for Liverpool), Olivier Giroud (+2 for Arsenal), and a small improvement over Romelu Lukaku at Everton. He’s also only a 1 point downgrade over Diego Costa and Sergio Aguero, and a 4 point downgrade over Harry Kane following his amazing season. Being an improvement over some great strikers, and basically break-even against world-class strikers like Costa and Aguero is pretty remarkable, and one could easily argue that only being a 4 point downgrade over Harry Kane given his amazing season is strong as well.
The Benteke finding is the most interesting one to me: Vardy was reportedly available for somewhere around £15 million, while Liverpool reportedly paid over £30 million for Benteke to score 4 goals in 14 appearances so far. My model would have identified Vardy as a better signing, and maybe Liverpool would have been the beneficiaries of the purple patch Vardy (and Leicester City with him) have gone through this season.2 With the margins being as thin as they are for the top 4, this knowledge could have been invaluable to Liverpool.
Other than Liverpool, my transfer evaluator shows him as a good backup for Aguero at Manchester City and Costa and Chelsea. City probably doesn’t need him with Bony as their #2 striker, but Chelsea would clearly have benefited from another striking option other than Loic Remy (especially given Jose Mourinho’s tactical nous that seemed limited to “We’re down a goal, replace a midfielder with a striker” for the first 15 games of the season or so). Distribution from Mahrez has been unbelievably important for Vardy, but Oscar/Willian/Hazard might all be having better seasons if they had Vardy to aim at.
The transfer evaluator clearly didn’t anticipate how big Vardy would have been this year, but it did recognize that he’s either an improvement or a decent replacement for many of the Premier League’s elite teams and did so before the season even started. Take it for a spin and see who your favorite team should sign for the second half of the season.
- I get 25 free “active hours” a month, and my Twitter followers used those up in 4 days this month. I’ve bought 500 hours to hold me through January 25 – hopefully that’s enough. ↩
- This all assumes someone provides at the level Mahrez has this year, which is a big assumption. Even if he didn’t score as many goals, he’s still a 3 point upgrade over Benteke given the underlying stats. Although given the price, maybe Liverpool could have signed Mahrez and Vardy for the cost of Benteke. ↩