xGenius: Expected Goals and the Science of Winning Football Matches

By James Tippett

The Expected Goals method, otherwise known as ‘xG’ measures the quality of chances that teams and players have at creating and conceding goals. Every shot which takes place in a football match carries an xG value: a shot from twenty-five yards might be worth 0.02(xG) and a tap in from inside the six-yard box would be 0.90(xG) while a penalty shot always amounts to 0.77(xG).

Initially used by betting companies and football clubs, the Expected Goals method has now made it into mainstream media with regular appearances on major broadcasting channels. The statistic is also a regular discussion point among football fans as they learn how to use the data to evaluate their favourite team’s fortune. Will a team’s undisturbed run of wins last? Football clubs, big and small, now turn to analysts to dissect each player’s every action and Premier League giants use the data to identify hidden gems in the transfer market and scout upcoming opponents.

Did you know that only about one in every nine shots in the Premier League ends up as a goal? Why Brighton are the unluckiest team in football history? What the ‘Timo Werner paradox’ is? How xG has changed how teams play football? James Tippett answers these questions and more in this definitive guide to Expected Goals analysis through real-life examples.