Goals in soccer can be greatly influenced by luck or random moments such as near misses, deflected shots, errors, or referees. Expected goals measures the probability that a shot will result in a goal. Factors include angle and distance to goal, current score, header or not, during a counter attack, etc. This statistic can be used to more accurately determine the performance of a team. If the score was 0-0 but the keeper's had 20 saves each, that score could have been 3-3 or more on another day.