Calculating a Team’s Ranking
for WFTDA Rankings
WFTDA Rankings Calculator
A team’s monthly WFTDA Ranking is based on the WFTDA Rankings Algorithm and is managed by the WFTDA Rankings Calculator. The WFTDA Rankings Calculator is available to WFTDA Member leagues at http://rankings.wftda.com/. Rankings are calculated monthly with public releases nine times a year due to the WFTDA Playoffs.
See the WFTDA Sanctioning Policy for information on the game types listed in this document and for all requirements for games to count towards a WFTDA Ranking.
WFTDA Rankings Algorithm
The WFTDA Rankings Algorithm is built on several formulas that calculate a weighted average of all games played in a 12-month period. This section details how these formulas are calculated.
A team’s ranking is determined by comparing its Rankings Point Average to that of other teams. Rankings are calculated at the end of every month.
Calculating the Rankings Point Average
A team’s ranking is determined by comparing its Rankings Point Average to that of other eligible teams. The Rankings Point Average is a weighted average of Total Game Points Earned for all sanctioned games played in a 12-month period.
Rankings Point Average = Total Game Points Earned in the 12-month period / Weighted Game Count of Games Played in the 12-month period
Total Game Points Earned
The sum of the Individual Game Points earned in the 12-month period
Weighted Game Count
The number of games played in the 12-month period, weighted semi-annually using a Decay Factor:
- Games played in the most recent six months of the 12-month rankings window have a Decay Factor of 1.0.
- Games played in the oldest six months of the 12-month rankings window have a Decay Factor of 0.5.
This weighted average of games played, in combination with the Decay Factor applied to game points (see below), ensures that teams who have played more games in the oldest six months of the 12-month period are not penalized, and allows for different season schedules.
Weighted Game Count = (# of games played in oldest 6 months * 0.5) + (# of games played in newest 6 months)
A team has played a total of 8 games in the 12-month ranking period, with 5 games in the most recent six months of the 12-month period, and 3 games in the oldest six months.
The Weighted Game Count will be:
5 + (3 x 0.5) =
5 + 1.5 = 6.5 Weighted Game Count
Calculating Individual Game Points Earned
Each sanctioned game contributes a set number of points towards a team’s Ranking Point Average using the following formula:
Individual Game Points earned = Win-Loss Factor x Opponent Strength x Decay Factor x 100
Each sanctioned game is worth a value of 3 points. That value is divided between the two teams based on the percentage of the total points each team scored in the game.
Win-Loss Factor = [Team’s Points / (Team’s Points + Opponent’s Points)] x 3.
Team A plays Team B and the score is Team A 200 – Team B 100. The total points scored in the game is 300.
Team A’s Win-Loss Factor is (200/300) x 3 =
.67 x 3 = 2.0 Win-Loss Factor
Team B’s Win-Loss Factor is (100/300) x 3 =
.33 x 3 = 1.0 Win-Loss Factor
Opponent Strength (Factor)
Each team is assigned a Strength Factor based on its Ranking Point Average compared to the Ranking Point Average of every other team.
Strength Factor = Team’s Ranking Point Average / Rankings Point Average of the Median Team in the Calculator
Strength Factors are calculated once each rankings period (currently monthly) and are valid for the entire period, regardless of whether games have been played in the current month.
The Strength Factors used for a game played on June 20 are based on the results of the May rankings. If the team played a game on June 10, this will not impact their June 20 Strength Factor.
The Minimum Strength Factor is 0.5. Unranked teams and teams whose natural Strength Factors (i.e. the result of the calculation) are lower than 0.5 are assigned a Minimum Strength Factor.