The method: The Elo rating system
Elo ratings are a calculation of performance in head-to-head competitions originally developed for chess. This method has been used to rate a variety of competitions, including soccer. For each team, the calculation considers final scores, margin of victory, home field advantage and strength of schedule.
Sportify builds on existing ELO methodology, improving the season starting rating by using a combination of a proportion of a team’s rating in the previous season and a proportion of the league’s average rating. Wins always add points and losses always deduct points. Unexpected results, such as the upset of a strong team by a lower rated team, cause a greater fluctuation in points compared to “expected” results.