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How the IFCA ratings are calculated

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How the IFCA ratings are calculated

Post by GTDon2 on Tue Aug 09, 2016 11:44 am

The IFCA ratings computer calculation is a modified Elo formula that accounts for multiple competitors instead of just 2.

The Elo rating system is a method for calculating the relative skill levels of players in competitor-versus-competitor games such as chess. It is named after its creator Arpad Elo, a Hungarian-born American physics professor.

The Elo system was originally invented as an improved chess rating system but is also used as a rating system for multiplayer competition in a number of video games and simulators such as iRacing, association football, gridiron football, basketball, Major League Baseball, Scrabble, snooker and other games.

The difference in the ratings between two players serves as a predictor of the outcome of a match. Two players with equal ratings who play against each other are expected to score an equal number of wins. A player whose rating is 100 points greater than their opponent's is expected to score 64%; if the difference is 200 points, then the expected score for the stronger player is 76%.

A player's Elo rating is represented by a number which increases or decreases depending on the outcome of games between rated players. After every game, the winning player takes points from the losing one. The difference between the ratings of the winner and loser determines the total number of points gained or lost after a game.

In a series of games between a high-rated player and a low-rated player, the high-rated player is expected to score more wins. If the high-rated player wins, then only a few rating points will be taken from the low-rated player. However, if the lower rated player scores an upset win, many rating points will be transferred. The lower rated player will also gain a few points from the higher rated player in the event of a draw. This means that this type of rating system is self-correcting. A player whose rating is too low should, in the long run, do better than the rating system predicts, and thus gain rating points until the rating reflects their true playing strength.

It takes about 10 races for a rating to become a solid average for any given driver.  In our system we also slightly weight the points formula for podium finishes.

A driver that is 75 points higher than another driver will gain no points for a win.  In this way a much higher rated driver can not continue to gain easy points against inferior drivers.

The IFCA ratings computer also indicates rating performance or how strong a driver was in a given race.  This is calculated based on the average driver ratings of the entire lobby.  This gives you some sense of the strength of the lobby and performance levels achieved.

In general the IFCA computer is very accurate at predicting outcomes.  The higher rated drivers are predicted to finish near the top, and the lower rated drivers beneath them. Occasionally a very fast driver can zoom to the top of the ladder with just 1 race by beating several high rated drivers, but this is only provisional and not a true reflection of the driver rating.  It takes at least 10 races for a rating to stabilize.

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Ratings adjustment

Post by GTDon2 on Wed Sep 14, 2016 10:21 am

Soon we will be doing a cleanup and ratings recalibration so the rankings better reflect their intended model.  This will not affect your current ranking as much as your numeric rating.  E.g., your rating will change but not your ranking as much.  This is so we can spread the rankings out and have a wider list that isn't concentrating everyone at the high, low, or middle.  We wanted to wait to do this after we reached 400 rated/ranked drivers.  This will give us a more even and accurate spread of talent as a result.  Expect to see this change soon.


Last edited by AAR GTDon on Mon Feb 20, 2017 4:21 pm; edited 1 time in total

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Ratings adjustment

Post by GTDon2 on Fri Sep 16, 2016 3:28 pm

Here at the IFCA we continue to try to improve and define console simulation racing and the skill level it takes to rise to the top, by calculating, categorizing, and then documenting your performances.  We do this through a rating's formula based on that of the Elo system which is used in many sports including our cousins over at iRacing.  The original system was invented for the game of all games, Chess, as a means of defining individual chess strength between the weakest and strongest players.  It is a tried and true method that can pinpoint your relative skill level compared to everyone else.  The only real difference is the scale that is used to define what is the weakest and what is the strongest numeric rating.

Recently we decided we wanted the ratings to more closely resemble the scale of international chess ratings as much as possible.  This allows us to keep ratings inflation under control (an inherent concern in the formula) and spread the different skill levels more equally apart.  As a result, you will notice that your rating has changed in order to mirror that of FIDE or USCF chess ratings, but your ranking has not.  In addition, we re-titled each skill level at 200 point increments.  So while your rating has been comparatively adjusted downwards in most cases, your rank has stayed the same, but your skill level title may have changed depending on where you fall within each 200 point sector.

We also updated the IFCA formula itself so that it is more linear with a steeper curve, meaning that those at the top are prone to less volatile ratings changes than those at the bottom.  The higher your rating the less your rating can change, while the lower your rating the more it can change.  

We also recognize 2 extremely high skill levels that are unique to the IFCA and not a part of chess. "Alien" (2800-3000) and "Legend" (3001+).  All other skill levels mirror the accepted levels in the USCF and FIDE.  To date no one has broken through to the 3000s, so we have no Legends, yet.  It would require several "Alien" level drivers to compete against each other to reach the unprecedented "Legend" skill level.

Many have asked, "How do I get on the list? Or, How did I get on the list? Any organized race with public results can be rated.  You can post the results here on the IFCA, or send us a link to the results.  To date, all of our ratings have come from racing events in TORA, DMR, IFCA, ESL, TURN, FMC, SimRacers, and host of smaller club events.


The new IFCA ratings scale

3001+ Legend
2800 - 3000 Alien
2600 - 2799 Grand Master
2400 - 2599 International Master
2200 - 2399 Master
2000 - 2199 Expert
1800 - 1999 A-Class
1600 - 1799 B-Class
1400 - 1599 C-Class
1200 - 1399 D-Class

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