# Help

# 5. The rating system

The rating system estimates the skill level reached by every player comparing with other players. The marks are always individual; when games are played by pairs or teams ranks are updated separately for every entrant.

Ranks are updated as a result of an elaborated calculation built according to the same usual criteria used for chess and other games. The aspects taken into account to update the scores are also explained in this page.

The use of the rating system is optional. The result of the game is taken into account when the player who opens the marks the *rated* option ( ). Players who have not activated the competitive mode won´t have the option to enter into the game.

These are the informations given by the rating system:

- One numerical score for every player in every game.
- Before starting rated games, according to the score of the entrants and the options of the game, the system gives an estimate telling the chance of winning for every player or team.
- You can view the current rankings that show players that have competed at during the last 3 days, and monthly rankings.
- Level information is shown inside a colored label (from white in the lowest level to black in the highest), in order to make easier the location of players in a certain level. Here are several examples of possible colored labels:

1000 |
1250 |
1550 |
1850 |
2150 |
2450 |
2750 |
3000 |
3500 |
4000 |
7000 |

Penalties

Scores could be reduced in these cases:

- The first player who abandons deliberately the game, forcing the opponents to play against a
*robot*, receives a penalty in the updating of the score when the game fichishes. This penalty is not applied when the player loses the connection.
- Ludoteka.com could reduce the score of players if the log of the games shows that they aren´t true played, but just fixed to increment the score of one of the players.

Remarks about the rating system

- The goals of the rating system are to provide some reference for players who want to value their own progress in every game, and make easier the location of opponents with a similar skill level. There is not any prize for reaching the top places of the rankings.
- Players, ranks and games recorded are not deleted from the database after at least one year without using Ludoteka.com.
- Usually players increase quickly their rate during the first games, until they are near their real level. Subsequently the score is not accumulated indefinitely; it is adapted gradually according to the skill level in relation to other players, varying according to the chance and improvements in the skill level.

Calculation of the score

Following, the aspects taken into account to update the scores:

- The default initial value is 1000 points.
- After every rated game the scores of the players are updated according to their results, their chances of winning, the game and the options used. If more than two players take part, the position is taken into account, so that it is better to be the second that being the last.
- Rates are updated whatever the reason why the game is finished. If someone loses connection the score is reduced in the same way, unless the game is cancelled. In games where 3 or more players take part, one
*robot* takes the place of the disconnected player, and the final result is taken into account as if it was the same player.

Just before the start of every rated game, the system performs an estimate of the chances that every player or team has to reach the victory in the game. These are the used variables:

- The difference between scores; obviously, the chances will be more unbalanced as long as the distance between them is longer.
- If the game uses random elements (cards, dice,...) the chances tend to be more balanced. The system use one different coefficient for every game that measures the relation between mark distances and chances to win; those coefficients are updated according to the mark statistics in every game.
- For the same game the chances are more balanced when the options imply a shorter game; for example, a card game played to win one only hand is more balanced than playing to win several hands.
- If the game is played by pairs or teams, the sum of the individual score values of every team is used to perform the calculations.
- The starting player has a certain advantage in some games (chess, for example). In those games the estimate is adjusted using a corrector coefficient obtained from the statistics of the results of the games played at Ludoteka.
- The estimate does not inform about the chances to finish in a draw; for those games that tend to finish frequently in a draw, the estimate will tend to be also more balanced.

At the end of the game the system alters the ranks of every player as a result of a calculation that uses very different factors:

- The difference between the corresponding value to the achieved
**result** (1 for the winner, 0.5 if it is a draw, 0 for losers) and the chance to win (measured as a value between 0 and 1). So, the variation is bigger when the *less favourite* player gets the victory.
**Length** of the game: the average length of the game and the used options (for example, in games where the goal is to reach a certain score, and board games which board size may be varied) are taken into account. The variation is bigger when the game tends to be longer.
**Experience and skill level**: as long as players lack of experience, because they have still played very few rated games, their rank vary faster. On the contrary, rank vary more slowly for players who have already played many rated games, since presumably their values may be considered more reliable.
**Score**: in most games whose objective is to reach a certain score and 2 players or teams take part in the game, when the player or team who loses gets an adjusted result the alteration in the ranks is reduced.
- If the game is
**cancelled** by any reason, ranks are not changed.

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