Quidditch Canada Rolls Out New Rankings Formula

The Gameplay Department, has overhauled the rankings formula in order to provide a more accurate overview of how our league teams stack up against each other. The revamping was led by the department’s Statistics Coordinator, Indiana Nikel. 

The new formula follows an Elo Ranking System. It was originally developed to rank chess players, but has been used in recent years by a variety of sports organizations to rank teams, and is successfully implemented by Major League Quidditch. The system enables us to better predict the results of games before they are played, and allows for better game analysis, and the potential for more interesting tournament schedules going forward.

All teams begin the season with the same initial rating. After each game played, the change in a team’s rating is calculated using the following formula:

Change in rating = k × (Result − Probability of Win)

Result is either 1 or 0, depending on whether the team wins (1) or loses (0). A team’s change in rating is greater if they win a match they were not expected to win, as compared to their change in rating if they win a match they were expected to win. A summary of how the rankings work can be found in our Rankings Brief, and a more thorough explanation of the Ranking Algorithm can be found here. Both of these documents are linked on our Policy page.

Throughout the season, separate rankings lists will be maintained for the Eastern and Western Region. The rankings list will be combined after the National Championship, where Eastern and Western Rankings will converge. Rankings will not be carried over from year to year. After each season concludes, each team’s ratings will reset until the first games for the next season are played.

The Gameplay Department has retroactively implemented this system for the previous three seasons, and the generated rankings have proven to be more accurate than what was previously being implemented.

Curious to see where teams stand now? Check out the rankings page for live updates throughout the season.