Internet chess ratings

Taken from ICC ratings help:

***** RATINGS *****

The Basics:

You can have 5 different ratings on the ICC. There are ratings for bullet, blitz, and standard, which are different speeds of regular chess. There are ratings for bughouse and wild, which are for chess variants. See "help definitions" for an explanation of what these mean. Type "finger" to see your current ratings.

To get a rating in one of these five categories, you only need to play a rated game. Do "set rated on" and then do "seek" to ask for a game. You can ask for any time control or chess variant you wish. Type "help seek" for more information. Unrated games will not count for your rating, but you are welcome to play unrated games.

Ratings usually range from 800 to 2800 on ICC, but there is theoretically no limit at either end. Beginners usually get ratings from 800 to 1200. People with ratings over 2200 are considered to be "masters". Grandmasters playing on ICC usually have ratings from 2400 to 2800. You can type "best" to see the highest-rated players on ICC. You can type "rank" to see where you stand among ICC members.

Ratings on ICC are similar to the USCF and FIDE, but are totally separate. Do "help survey" for a statistical comparison.

A player's rating is "provisional" if he/she has played less than 20 games. A rating is "established" if it is based on 20 or more games. A different formula is used to calculate ratings for established and provisional players. See "help provisional" for some information about provisional ratings.

Everything you wanted to know about rating formulas, but were afraid to ask:

The rating during the provisional period is the average of a set of values, one for each game played. The value for a game against an established player is the opponent's rating plus 400 for a win and minus 400 for a loss. For a game against another provisional player, the value is moved towards the previous average to lessen the impact of the unreliable result. Players with no rating are treated as having rating 1650 in this case. Extra points are then added to the rating for the purpose of keeping the average rating of all established active players close to 1650. In particular, 1/5th of 1650 minus the current average is added to the rating.

To explain the established period requires the use of a formula. Suppose your rating is r1, and the opponent's is r2. Let w be 1 if you win, .5 if you draw, and 0 if you lose. After a game, your new rating will be:

1
r1 + K (w - (-----------------))
(r2-r1)/400
1 + 10

I still need to explain the variable K. This is the largest change your rating can experience as a result of the game. The value K=32 is always used for established player versus established player. (The USCF has a system in which this K-factor diminishes for more highly rated players.) If you're playing a provisional player, the factor K is scaled by n/20, where n is the number of games your opponent has played. So, as in the provisional case, if you play an opponent who has never played, your rating can't change.

This formula has the property that if both players are established then the sum of the rating changes is zero. It turns out that if the rating difference is more than 719 points, then if the strong player wins, there is no change in either rating.

Note that during the provisional period, BEATING a player whose rating is more than 400 points below yours will DECREASE your rating. This is a consequence of the averaging process. It's useful too, because it prevents the technique
of getting an inflated provisional rating after one game, and then beating 19 weak players to get an established rating that is too high.


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Rating Survey by Tmeister

Total responses so far: 670

People with ICC and USCF ratings: 592 ICC average rating = 1800
Less than 200 point difference: 397 (67%) USCF average rating = 1718
People with ICC above USCF: 385 The average difference: 82
People with ICC below USCF: 203 The median difference: 72

People with ICC and FIDE ratings: 107 ICC average rating = 2295
Less than 200 point difference: 83 (77%) FIDE average rating = 2233
People with ICC above FIDE: 71 The average difference: 62
People with ICC below FIDE: 36 The median difference: 68

Tmeister's Rating Survey! Thanks to all who participated by sending data! All numbers and text were compiled and written by Tmeister. Minor editing and a couple comments added by POTZY. April 2, 1996.

Here is most of the useful information I found by studying the relationship between ICC ratings and national ratings. First of all, I could only compare ICC ratings to ratings from USCF, FIDE, WBCA, and USCF Quick ratings. There was so little data for the other national ratings that I could not conclude anything really meaningful. For most of the comparisons, I used only players whose ICC ratings had been active for at least one of the times I tested their rating. Another thing to note with that is that the ICC ratings used for each player was an average of their rating tested three times over a two month period, with no less than ten days between tests. this way I hoped to eliminate the fact that ICC ratings vary a lot. For those tests with not very many data points, I included those players who were inactive, but under no time did I use a player who was provisional during one of the times I tested the rating.

First, the comparison of ratings between USCF and ICC-BLITZ. The first item is ICC Rating, a grouping of all players with ICC ratings in that range. data points are the total number of active players in that group, and trimmed is the % of data values trimmed from the top and bottom, to eliminate others. the mean is the average value of the difference between each player's USCF rating and ICC rating (a positive value means the player's USCF rating is larger than the ICC rating).

Comparison of USCF to ICC Blitz Rating

ICC rating Players trim mean StDev
OVERALL 195 10% 98.6 124.7
2400+ 6 0% -103.9 99.6
2200+ 28 10% -39.8 61.0
2200-2400 22 10% -24.5 66.2
2000-2200 20 10% 112.0 85.8
1800-2000 37 10% 99.9 120.5
1600-1800 35 10% 209.7 81.3
1400-1600 36 10% 107.2 137.0
1200-1400 23 10% 60.6 160.3
1000-1200 16 10% 116.2 104.9

What this means is, if your ICC rating is between 1800 and 2000, you can expect to have a USCF rating of approximately 100 points higher than your ICC (Blitz) rating. Looking at the data, overall, ICC blitz players are underrated (as compared to USCF rating) by almost 100 points. Those with very high ICC ratings are overrated, however, those with ratings below 2200 are on average underrated. It was very interesting to find the mean of 1600-1800 group. Also interesting that this group has a much lower standard deviation than the nearby groups. One theory I can come up with is that there are many players of this strength playing on ICC and that competition is very fierce.

Comparison of USCF to ICC Standard.

The introduction to this part is the same as the introduction to the previous part, comparison of USCF to ICC Blitz.

ICC Rating Players trim mean StDev
OVERALL 95 10% -82.4 124.1
2400+ 6 0% -170.4 119.9
2200+ 12 10% -168.8 105.3
2200-2400 6 0% -185.2 183.5
2000-2200 14 10% -13.3 110.4

1800-2000 31 10% -64.3 118.6 USCF=ICC (-64)

1600-1800 15 10% 50.1 88.3 ICC+50=USCF
1400-1600 13 10% -199.9 132.3
1300-1400 3 0% -65.2 150.6

What this means is, is your ICC Standard rating is between 1800 and 2000, you would expect to have an USCF rating around 64 points below your ICC rating. An interesting thing to note is that for the group 1600-1800, their expected USCF rating is above their ICC rating. (and like in the last comparison, this is the group with the smallest standard deviation.) This group, like the subsequent ones, have a rather small amount of usable data points, which means the data is not
very reliable.

Comparison of FIDE to ICC Blitz

ICC rating Players trim mean StDev
OVERALL 38 10% 30.5 124.1
2400+ 9 10% -180.3 66.7
2200-2400 13 10% 6.2 110.9
2000-2200 10 10% 109.6 74.8
1900-2000 5 0% 251.2 74.1

Very interesting to note that for those with ICC rating of over 2400 they can expect a FIDE rating of almost 200 below the ICC rating. and those with ICC rating of under 2200 can expect a FIDE rating of more than 100 points above. This amounts to a rather meaningless comparison of the two ratings. It seems that you have to be skilled at playing on ICC in order to have a high ICC rating, and a good FIDE rating will not matter as much.

POTZY: No FIDE ratings under 2000 exist. Only 35% of FIDE ratings are in the range 2000-2199. Therefore it would be expected that the people with ICC ratings 1900-2200 shown above would have much higher FIDE ratings. This is indeed true in the chart above. The data in the chart don't really say much, except that almost all FIDE rated players who
responded to the survey have FIDE ratings in the range 2200-2400.

Comparison of WBCA to ICC Blitz

ICC rating Players trim mean StDev
OVERALL 32 10% 52.2 120.3
2200+ 12 10% 42.4 86.4
1800-2200 12 10% 45.8 106.4
1100-1800 8 0% 98.0 226.5

POTZY: WBCA ratings are roughly 50 points higher than ICC Blitz ratings.

USCF Quick to ICC Blitz

ICC rating Players trim mean StDev
OVERALL 22 10% 114.8 140.9
1800-2500 10 10% 63.8 61.8
1100-1800 12 10% 163.6 182.2

All players in these groups should expect USCF Quick Rating higher than their ICC blitz rating.

#of respondents for each ratings type:

USCF 248
FIDE 43
WBCA 35
USCFQ 22
CFC 16
Australia 8
Iceland 7
Sweden 6
Germany 6
Quebec 4
Netherl. 3
Finland 2
Israel 2
IECG (internet email chess group), Wales, Norway, greece, Catalan, Spain,
Switzerland, Russia, Denmark: 1

All statistics and comments courtesy of Tmeister. Please ask permission from Tmeister before reproducing any of the rating study. Thanks