The Michi-chan Arizona Power Rankings

Updated: June 20 2026

From 2008 through 2011, Michi-chan tracked the Arizona Power Rankings.  This was during a time when there were a lot of home teams in roller derby.  Not until the 2010s was there a significant number of games where a team of one league would play a home team from another league.  This would lead to the Arizona Roller Derby Conference, which was a competition of many of the "state level" home teams leading up to a bracketed tournament at the end of the year.  With the 2020 crud and derby's rebuilding after that, the home team concept came back on a much smaller scale.  One notable thing about the original Michi-chan Arizona Power Rankings was that it spanned multiple rulesets putting the home teams of independent leagues such as Arizona Derby Dames, Arizona Rollergirls and Desert Dolls Roller Derby (now Phoenix Roller Derby) on the same level as the home teams of the leagues playing the WFTDA ruleset.  

In 2026, Michi-chan Sports has revived the Arizona Power Rankings, modeled after the Michi-chan DMVDerby Power Rankings (for DE, MD, VA and DE).  Instead of looking at the home team games, we are looking at interleague games at the league level.  Like the original Arizona Power Rankings, the revived rankings does not just look at WFTDA rules, but also at leagues that play USARS, MRDA and even RDCL banked track.  As mentioned, only "inter-league" games are considered.  Home team bouts within the same league are not included.  Read on to learn about this exciting new method of ranking the leagues!

Objective

To create a rankings system that in an environment where there are multiple leagues (entities) and where there is not a level schedule of games (e.g. one league may play 3 eligible games per year while another league plays 6).  The system must afford similar opportunities for rankings to leagues that have fewer game opportunities while acknowledging their achievements in those games.  The system must also address the unique structures of teams within each league.

The decision to center the rankings on leagues as opposed to teams are also intended to acknowledge the training, coaching, athleticism and overall culture at the league level.  Not only all of that, but it is also a wonderful opportunity for bragging rights. 

Eligible Leagues

Each league would be considered an “entity”.  Any team roster from that league would be considered representing that entity.  Therefore, the team’s level (A, B, etc.) would not be taken into consideration.   Only leagues that are based in the state of Arizona are eligible to be an entity.  Statewide, borderless and collective teams cannot be eligible entities.   As of June 19, 2026, the following Arizona leagues/entities are eligible for ranking.  These are also the names recognized in the event of a tie in rankings (second tiebreaker): 

• Arizona Derby Dames
• Arizona Roller Derby
• Arizona Rollergirls
• Arizona Skate Club
• ASU Derby Devils
• Bordercity Rollergirls
• High Altitude Roller Derby
• Northern Arizona Roller Derby
• Phoenix Roller Derby
• Tucson Roller Derby
• UA Derby Cats

Eligible Games

 Only games that are played involving at least one Arizona entity will be considered.  The following games are not eligible: 

1. “Home team” games played between two teams from the same entity (for example AZRD Bad News Beaters vs. Skate Riot Project);
2. Any games that include at least one multi-league mash-up team, even if all of the leagues represented are eligible entities (e.g. “the world”);
3. Any game that ends with a tie score;
4. Any otherwise eligible game where the total number of points scored between both teams is less than 150; and
5. Any game where there are scoring deviations from the standardized rule set (e.g. “shenanigans” games).
6. Juniors games.

Games that are stopped before the end of the second period will be considered complete games as long as there have been at least 150 points accumulated between both teams.

Unlike the former Arizona Power Rankings, the 2026 era Michi-chan Power Rankings are compatible with different rulesets such as WFTDA, USARS, MRDA and RDCL without specific adjustments for each ruleset. Entities on banked track will be combined in the rankings and will compete with flat track entities. Likewise, entities that do both banked and flat track will have all of their games combined into the single entity. 

We have no plans to rank juniors with adults.  If there is a massive growth of juniors in the region, we may consider a separate Power Rankings for juniors, but we are nowhere near that point.

All adult entities will compete with each other without regard to gender. 

Eligibility Period

Games that are considered eligible towards an entity’s total power score are limited to those played within the past 365 days (1 year rolling calendar).  Once 365 days have passed since the game was played, the game will age-off and the entity power score will be recalculated and the entity will be reranked.

Rankings Updates

The Power Rankings will be a daily systematic live ranking with the updates performed at around 3:10AM Arizona Time (AZT).  Rankings will be based on all scores of qualified games already in the database as of when the daily run is made.  Any delays on getting a final score to Michi-chan Sports and it being entered into the database will skew the results until the data is entered. The Power Rankings source code and formulas do not involve any kind of AI.  During this run, all games scheduled in the future will be updated with the rankings of the leagues involved.  The final ranking to determine the parameters used for that game will be those that were ran at 3:10AM AZT on the day of the game.

Raw Margin Score

The raw margin score is calculated by first adding up the total number of points scored by both teams of the game, dividing the number of points scored by the winning team into the number of total points scored and then multiplying that number by 100.

For example: The final score of the game was 161~85.  A total of 246 points were accumulated.  Divide 161 by 246 to reach 0.65447.  Multiply by 100 to reach the margin score of 65.447.  In other words, 65.447% of all game points can be attributed to the winning team. 

((WinScore / (WinScore+LossScore)) * 100)

"Underdog" Adjustment

In order to recognize games that are won by lower ranked entities, we will add an additional “bonus” to the Raw Margin Score.  The bonus will only be applied if the lower ranked team (higher ranking number) wins the game.  The ranking differential will be based on the whole number difference in rank between the two entities divided by the number of entities qualified to be ranked on game day.

((RankOfTheHigherRankedEntity – RankOfTheLowerRankedEntity) / TotalRankedEntities)

Underdog adjustment is only in effect if there at least 5 ranked entities.  Only games played after June 19, 2026 will be considered when tracking past performance for the underdog adjustment.

The adjustment will be based on the value of the equation above:

• If less than 0.200, there is no adjustment.
• If greater than or equal to 0.200 and less than 0.400, an adjustment of 5% will be given.
• If greater than or equal to 0.400 and less than 0.600, an adjustment of 10% will be given.
• If greater than or equal to 0.600 and less than 0.800, an adjustment of 15% will be given.
• If greater than or equal to 0.800, an adjustment of 20% will be given.

In cases where the lower ranked entity wins, the Underdog Adjustment will reward the winning team and penalize the losing team.

The underdog adjustment is only applicable in games where both entities are considered Arizona leagues and both entities already have a ranking.

As an example, let’s say there are currently 7 entities eligible for ranking, the raw margin score is 65.447 (from the example above) and the lower ranked team (higher ranking number) wins:

RawMarginScore + (RawMarginScore * Adjustment) = GameMarginScore

Entity Power Score

The entity power score is determined by determining the sum of the margin scores of all eligible games won (PSW) and then the sum of the margin scores of all eligible games lost (PSL). Both values include any underdog bonuses that were applied.  The PSL is subtracted from the PSW and then divided by the number of games played in order to reach the entity power score.   The entity power score will be rounded to the nearest thousandth (3 digits to the right of the decimal point). 

For example, an entity has played four games, they won three games and lost one, the sum of the margin scores of the games won was 165.38 and in the game that was lost, the margin score was 51.62.  By subtracting 51.62 from 165.38, you would get a value of 113.76.  That value is then divided by the total games played (4) and results in an entity power score of 28.440.  The entity ranking will be based on that entity power score.

((SumOfWinningMarginScores – SumOfLosingMarginScores) / GamesPlayed)

In games where an Arizona entity plays against a non-Arizona entity, only the Arizona entity will have the margin scores considered for either a win or a loss. The league outside of Arizona will not be tracked and thus not eligible for a ranking.

Ranking

Rankings are based on the descending order of the power score for each eligible entity with at least 3 qualifying games played in a 365-day rolling calendar period.  In the event of a tie in power scores at the thousandth level, the first tiebreaker will be number of wins, the second tiebreaker will be the total number of points scored by an entity in all eligible games and the third tiebreaker will be the league name in alphabetical order.

In order to receive a ranking, an entity must play at least 3 qualifying games in a 365-day rolling calendar period.  Entities that currently do not have 3 qualifying games in a 365-day rolling calendar period will not receive a ranking even though their games will still be tracked and they will receive a ranking once they have achieved 3 games within the 365-day period.

Historic Snapshot

While live rankings are published on a daily basis, only those rankings that were executed on Tuesdays and Fridays will be a part of the permanent historical record.  The Tuesday rankings will be used for any display that shows whether an entity has gone up or down in rankings over the week.