In detail

There have been numerous requests for revealing the Playray ranking formula and we, at Playray, have listened to you. Because it is hard to create a system that would be simple, cheat-resistant and fair, we have opted to go the complicated way. Therefore, our detailed ranking system explanation will most likely appeal only to the most mathematically inclined Playrayers.

Points	Icon	Title (unofficial)
0		(no games played)
1 - 49		Newbie
50 - 99		Beginner
100 - 199		Novice
200 - 299		Amateur
300 - 399		Advanced
400 - 499		Expert
500 - 599		Professional
600 - 699		Champion
700 - 799		Sapphire Guru
800 - 899		Ruby Guru
900 +		Diamond Guru

There are three components for the ranking calculation: 1) the success in games 2) experience and 3) the idle factor.

The success in games

The success in games is calculated by using various weighting factors that are derived from different opponent levels.

The opponent level is determined in two-player games by the difference in players' rankings in that game. The opponent level in multiplayer games is defined by the average of rankings of the other players. If there are any guest players in the multiplayer game, the ranking level will be "against a guest".

Here are the equations to determine the player level difference:
if
opponent rank <= 300*((ranking-300.0)/700.0)
then the game is against a much worse opponent
if
opponent rank <= 700*((ranking-100.0)/900.0))
then the game is against a worse opponent
if
opponent rank >= 300.0+(1000.0-300.0)*(ranking/900.0)
then the game is against a better opponent
in other cases, the game was against an equal opponent.

For example, if your ranking is 400, then the opponent would be

• much worse if the opponent's ranking would be below 42,8
• worse if the opponent's ranking would be between 42,8 and 233,3
• better if opponent's ranking would be over 611,1
• equal if opponent's ranking would be between 233,3 and 611,1

Weighting factors

For example, a win against a better opponent is worth two points, a loss against a worse player is worth -1,5 points. For example, if the player has played 3 games, all against the same level opponents, winning two and losing one, the score will be ( 2*1,5 + 1*-1,0 ) / 3 = 0,67. This figure is multiplied by 400 to scale it to Playray ranking, so, the ranking score would be 266,67.

However, this has to be scaled to the amount of played games, because otherwise one victory against a better player would slingshot the ranking to 800 right away. The scaling factor starts from 0,015 and will gradually increase to 1,0 which is reached as the player has played 500 games.

Experience points

The player can get up to 200 experience points from playing games to the finish. If the player leaves the game before it is finished, no experience points are earned.

The maximum amount of experience is reached after 500 games. The experience points can not decrease, so games played after these 500 games do not influence the experience points at all.

The idle factor

The idle factor was introduced to the ranking system in late 2006. The idle factor is a number between 0 and 180, which indicates the activity of the player in the game.

Every night, if the player has not played during that day, the idle factor increases by one. If the player has played a game during that day, the idle factor decreases by three.

The idle factor starts to influence the ranking only after it reaches 30. If the idle factor is below 30, ranking is multiplied by one (ie. no influence) and if the idle factor is 180, the ranking is multiplied by 0,6 (ie. you lose 40% of your ranking if you are inactive for 180 days). The multiplier decreases gradually between 30 and 180 from 1 to 0,6.

Overall ranking is a weighted average of the player's best rankings in different games. The weighting factors are the following: 987, 610, 377, 233,144, 89, 55, 34, 21,13, 8, 5, 3, 2, 1.

For example, if the player has played only three different games and the rankings are 100, 400 and 200, the ranking is calculated as followed:
( 400*987 + 200*610 + 100*377 ) / 2582 = 215

Duration of games

A limitation in the duration of games was introduced in late 2006.

Only the games that take longer than a certain period of time influence ranking. This period of time is very short, typically only from 10 to 30 seconds, depending on the game (chess games are never below 30 seconds, 9-ball pool games might sometimes be over in seconds).

This limitation has been made to make cheating harder. Before the change it was rather easy to cheat by playing against oneself in another browser window and quitting one game after another with rapid pace.

Your feedback

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