X is for xG in Football Manager by @nturner2202

How often have you watched a game, whether on FM or in the real world, where you have battered the opposition but come away with a loss? This happens all the time; the overall result usually doesn’t tell the full story of a match.

Commonly, this is known as “getting FMend” (links to the FM sanity support group are included below). 

Before you click that link, though, have you thought of looking at your expected goals?

Okay, technically, “expected goals” isn’t an X. However, unless you want an article on the xenophobia of the work permit system, X-rays, or FM24 has an unexpected xylophone feature in development, then you will have to go with it.

So, what is xG? In as simple terms as possible, xG measures the probability of a shot resulting in a goal. For example, a shot with an xG value of 0.5 has a 50% chance of being converted and therefore should result in a goal 1 in every 2 attempts.

This is all dependent on a myriad of factors. Such as the angle of the attacker when striking the ball, the positions of defenders, who the opposition goalkeeper is, what the striker had for breakfast that morning, whether a seagull is flying over the stadium at that precise moment, and which way the wind is currently blowing.

In football, expected goals have now become a commonly used way to analyse a team’s performance (in addition to completed passes in the final third and standard shots on/off target).

The xG system was developed because, to put it bluntly, goals are the most important thing in football. They are the lifeblood. A full stadium doesn’t erupt in celebration of 65% possession. No one signs up for a season ticket on the basis of over 4 corners per half. Most games end with less than 3 goals, meaning goals are the rarest occurrence in a match (unless you are a Manchester City fan) and therefore the most valuable.

By developing a system to check how many goals a team should score, it became easier to find trends throughout matches and seasons to give a clearer picture of exactly what’s happening on the virtual pitch.

Following early usage in the betting markets, xG has become a mainstay on Sky Sports and Match of the Day, as well as being included in the past few editions of Football Manager. If a metric is being shown by Gary Lineker every Saturday, surely, it’s worth a few moments of your time. 

Professional clubs also know the power of xG and have also cottoned on to the fact that it’s not just during a match that Expected Goals can help influence your decisions. xG can show areas of your squad that need strengthening in the transfer window. Does your defence concede a lot? Check your xG! Is your striker misfiring? Check your xG! No left-backs fit for your next match? xG won’t help, but it’s worth checking anyway. 

The FM community, in particular, through playing a simulator, will likely have a great understanding of these stats and how that translates into performances. Although a red line should be drawn here, there is a difference between “Flight Simulator” and being a pilot.

So to be clear, I’m not a data analyst. Trying to deduce too much data is surely a recipe for madness. I can imagine most data analytics meetings being somewhere between a stock exchange trading floor and a counselling session.

Metrics may help narrow the margin of error, but be warned! Data (xG or otherwise) doesn’t win football matches, and performance statistics don’t ensure a player fits with your style.

Going back a few years, “dinosaur” Big Sam Allardyce revolutionised recruitment by using data to band together a rag-tag bunch of football misfits and has-beens. This was a little more complex than selecting contracts “expiring”—world reputation “very good”. 

With next to no money, he took Bolton out of the Championship, into a cup final (which they lost to the mighty Middlesbrough), and into Europe.

This has been refined over time, resulting in the massive influx of fancy new stats that pop up randomly during match coverage: “As you can see below, Declan Rice’s hairline has the shortest distance to his eyebrows on the pitch, and he has also won the least amount of headers today. Coincidence?”.

Brighton and Brentford are two current examples of Premier League clubs that have incorporated xG (amongst other data elements) into their recruitment policy and are getting the benefits with performances well above their perceived standing in the game. They restructured the recruitment set-up with the help of Expected Goals to find undervalued players. This has allowed them to slowly but surely lay the foundations to play well above their means, and they currently find themselves troubling the big boys in the Premier League.

Think of it like this; are you scoring less than your xG? If so, then perhaps you need more clinical finishers. You could then use your scouting network to find players that are performing well above their xG average and filter them by price to ensure you get a good deal (thank me later).

There is no sure-fire way to win in Football Manager (aside from reloading). Just like the results of real football matches are frustrating and unpredictable, the results in FM are just the same. 

However, the Expected Goals stat can be one of the most powerful indicators of how your team is performing and could give you the insight you need to understand what is happening out on the grass (and why you keep getting FMend).

For previous A-Z entries, please visit: The A-Z of Football Manager.