Rules of Self-Rally Player Rating System

Self-Rally.org Platoon uses Elo Rating System for rating players. Ratings try to tell the strength of a player by his historical performance against other players. Ratings do not try to reward or punish players in any manner, but simply provide an educated guess how likely player A is to beat player B. As more evidence is gathered (=player plays more rated games), more accurate the suggested rating gets.

General Rules

All new players get 1500,0 rating points when they enter the system

Any player with less than 10 rated games has a provisional rating. The tenth rated game automatically converts the player's rating into a non-provisional rating = ''official Self-Rally rating''

If either of the players have a provisional rating, the game result is considered as a provisional game: if both players are provisional players, neither player's rating is changed (but the game is counted towards the limit of 10 games to get a non-provisional rating for both players). If exactly one of the players is a provisional player, only his (provisional) rating will be adjusted and the non-provisional player retains his pre-game rating.

All gaming results have exactly one winner and one loser. Ties for rated games are not possible, neither games with anything else than 2 Self-Rally rated players

A new rating is calculated after every game. Our web-site does that automatically (see later).

A player who does not have at least one rated game for a period of 12 months becomes inactive in the end of the current month. Inactive players lose their official ranking, but they retain their rating. As soon as an inactive player plays a rated game, he becomes active from the beginning of the current month, and he is moved back to the official ranking list.

Mathematical details

Any non-provisional game result will have zero net-effect on the total sum of the rating scores in the system. The winner gains exactly as many rating points as the loser looses. An average player has a rating of 1500,0 points, and in theory, 50% of the players are in the range of 1400,0 - 1600,0.

All ratings, and the changes made to the ratings, are maintained with one digit accuracy. After the points have been calculated, any fragments beyond 1/10 are lost as the change has been calculated and stored in the rating database.

The mathematical details can be found in the Wikipedia article on Elo Rating System. Self-Rally Platoon uses the original formulas given on the article (assuming normal distribution of player strength)

The K factor = 32 for all the players / games, so the maximum rating adjustments for any gaming result ranges between -32,0..+32,0. For equally strong players (having the same rating), the winner gains +16,0 pts and the loser -16,0pts. If an indefinitely weaker player wins indefinitely stronger player, he gains +32,0 pts, and -0,0pts is he loses (gaining or losing 32,0 pts in one game is never possible in practice, since an indefinitely strong or weak player do not exist).

About Entering Results

A game that was agreed by the players prior the game start to be included in the official games can be entered into Self-Rally rating database by any supporter of Self-Rally Platoon Ry (only the supporters have the required password to do it)

The game must be entered within 1 month from the game end. Older results will not be accepted by the rating system. In case either of the players has a gaming results ended later than the one being entered, the rating system will re-calculate all the ratings from the time of the currently entered historical game.

Grace period: No matter when the gaming result was entered into the rating system, it may be changed by the players until one month has passed from the game end. After the month has passed, the result becomes final, and cannot be removed or changed anymore. This is to protect the system against the snow ball effect of the historical games to the current ratings.