Ranking basics
Base rank
A player's ranking is always between 0 and 1000. In each MERS tournament
he can obtain a base rank between 0 and 1000. The player's total ranking
is a weighted average of his obtained base ranks from the tournaments he
has participated in.
A player who wins all his tournaments, will have a total ranking of 1000. A player who loses all this tournaments, will have a total ranking of 0.
Weight
Results from certain tournaments, count more towards a player's
ranking, than results from local tournaments do. These weights are
related to the MERS qualification of a tournament: OEMC and WMC
count five times, national championships count two times and other
(local) tournaments with a MERS-1 qualification count only once.
Also, a player's older results count less towards his ranking, than his more recent results do. Tournaments over two years old have half the weight and when a result is over four years old, it will no longer contribute to the MERS.
Minimum requirement
To establish a representative ranking five
results are needed. A player is required to have
participated in at least two
tournaments to appear on the ranking
and a player with less than five tournaments is given a result of 0 (weight
1) for each missing tournament.
Calculation
A player's base rank in a tournament is based on his place in the
tournament compared to the other participants:
- If you win you get a base rank of 1000.
- If you are in the middle of the field you get a base rank close to 500.
- If you are number 75 out of 100 you get a base rank of 252.
- If you are last of 100 players, you get a base rank of 0.
The base rank is calculated as follows:
- Find the number of player's you have beaten by taking the number of players and subtract your position.
- Divide by (number of players minus 1).
- Then multiply by 1000 to avoid small numbers.
Example: there are 100 players. Consider the player who got the 25th place. Base rank: (100-25) / (100-1) * 1000 = 757.
Averaging
When a player has participated in several
tournaments, you take the average of all the base ranks he has
obtained and this is his total ranking. So a player who got base
ranks 200, 500 and 1000 in the 3 tournaments he has participated
in, would have a total ranking of (200 + 500 + 1000)/3 = 567.
This is the general principle, without minimum requirements or
weights.
Now, since tournaments are rated differently, consider a player who has won an OEMC (100 players) and he became number 25 out of 50 players in Danish Open. The base ranks for these tournaments are 1000 and 510. If we take the average, he would get a total ranking of 755.
However, the OEMC is rated MERS-5 and the Danish Open is rated MERS-2. Instead of a normal average, we make a so-called weighted average:
(5*1000 + 2*755) / (5+2) = 930.
And a player who was 50 out of 100 in an OEMC and has won the Danish Open, will have base ranks 505 and 1000. Almost the same as the previous player, but when we calculate his weighted average, he end up wiht less points:
(5*505 + 2*1000) / (5+2) = 646.
Reporting Results
Sébastien Berret is maintaining the MCR and Riichi ranking
database, so organizers are kindly asked immediately after tournaments
to:
- always use this Excel sheet for reporting tournament results
- always check that all EMA ID's for European players are correct. (Non-European players don't have EMA ID's.)
- Use this form to send the results to Sébastien.
