What are expected goals in football?

Expected Goals, xG - is the indicator of expected goals in football matches. xG model assigns a score to each chance, representing the likelihood of that chance resulting in a goal. xG fix the shot in the exact moment when the players leg touch the ball.

xG depend on many factors which could be divided into main and secondary factors. Main factors in xG model are such metrics as distance to the goals, the angle of a shot, goalkeeper’s position, the number of backs which blocks the shot and their positions.

Secondary factors: forward’s and goalkeeper’s skills, the type of assist and the place of assist, the type of a shot, the distance ran by the player and the time he spent on the field.

Score, players mood, weather and other factors can also affect on the xG, but this factors are not so important and hard to score.