Spinchat.com Help and Information System

# How do the ranking lists work?

**What is a rating?**

The rating is a variable which is meant to show the probable playing strength of a player as closely as possible. There are various rating procedures which can be used to determine this variable.

**Where do I find the ranking lists?**

You can find the ranking lists under "Games" -> "Multi-player games" under the respective game.

**Why am I not on the ranking list?**

Simply play more ranked games against other registered players. You will appear on the ranking list sooner or later.

**How does the ranking list work?**

We use a procedure developed by Prof. Mark E. Glickman, the so-called "Glicko Rating System".

The procedure makes use of methods from applied statistics, in order to determine the rating iteratively from the results of games. The Elo rating system, made popular by chess, is a special case of the Glicko System, according to Prof. Glickman.

For the iterative calculation of a ranking, the procedure makes use of the ranking of the players (WZ), the ranking deviation (WA) prior to the game and its result.

You can find a detailed description of the applied methods here.

**What's the point of the ranking deviation number?**

The WA records how well the WZ already corresponds to the real playing strength of a player. The interval [ WZ - 2 * WA , WZ + 2 * WA ] corresponds to a 95% confidence interval, i.e. the real playing strength of the player lies with a 95% probability within the interval.

From this, it hence follows that the smaller the WA, the more exact the rating already recorded.

**I have already played quite a number of games. Why am I not on the ranking list?**

Only players whose WZ has already been isolated with sufficient accuracy, i.e. the pertinent WA has to be smaller than a specific threshold, will appear on the ranking list.

**I have played just as many games as X. X is on the ranking list, but I'm not. Why?**

X has a lower WA despite the same number of games; i.e. in order to determine the WZ at the beginning as quickly as possible, play

- against players whose playing strength corresponds approximately to yours.
- against players who have a low WA themselves.