Rating Histogram Comparisons

This article provides a table and two graphs comparing three Go rating systems (AGA, EGD and KGS). A chess rating system (USCF) is included for those interested in comparisons, or more familiar with it.

Table of contents
Table Comparing the Cumulative Histograms of Several Rating Systems

Notes

Cumulative distribution function

Cumulative histogram

Data sources

Related links

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Table Comparing the Cumulative Histograms of Several Rating Systems

This table shows the rating you need to be at a given percentile of the players in each rating system.

Cumulative histogram comparison table
Percentile	AGA ^[1]	EGD ^[2]	EGD rank	KGS ^[1]^[3]	USCF^[4] (chess)
1%	-34.61	100	> 20k	-24.26	444
2%	-32.58	100	> 20k	-22.30	531
5%	-27.69	153	20–19k	-19.20	663
10%	-23.47	456	17–16k	-15.36	793
20%	-18.54	953	12–11k	-11.26	964
30%	-13.91	1200	9k	-8.94	1122
40%	-9.90	1387	8–7k	-7.18	1269
50%	-7.10	1557	6–5k	-5.65	1411
60%	-4.59	1709	~4k	-4.19	1538
70%	-1.85	1884	3–2k	-2.73	1667
80%	2.10	2039	1k–1d	-1.28	1807
90%	4.71	2217	2–3d	2.52	1990
95%	6.12	2339	3–4d	3.88	2124
98%	7.41	2460	4–5d	5.29	2265
99%	8.15	2536	5–6d	6.09	2357
99.5%	8.70	2604	~6d	7.20	2470
99.9%	9.64	2747	7–8d / 2–3p	pro	2643
top	10.12	2809	8d / 4–5p	9p	2789

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Notes

[1] KGS and AGA ratings are in AGA form: ``n`` kyu ≈ ``-n``½, ``n`` dan ≈ ``+n``½, with a jump from -½ to +½.
[2] The EGD cuts off at rating 100 = 20 kyu. This distorts the EGF graphs for the 1% and 2% percentiles.
[3] The 99.9% and top rating for KGS have been estimated as 2850 (8.5 dan amateur) and 3000 (10 dan amateur).
[4] USCF (United States Chess Federation) ratings, e.g. a master has a 2200 rating.

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Cumulative distribution function

The following diagram plots the four rating systems as a [ext] cumulative distribution function: the vertical axis shows the percentage of players up to the level indicated along the horizontal axis. The top scale shows USCF ratings, while the bottom scale shows AGA ratings^[1].

Rating histogram

Usage Example: You have rating 2000 USCF, and are curious what that is equivalent to in go. Find the point where the USCF graph crosses 2000, which is at about 90%. Then move straight up to see where the other graphs cross that percentile, which is (roughly) 2200 EGF (2 dan), 3 dan KGS and 5 dan AGA.

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Cumulative histogram

The following diagram plots the same data as a [ext] cumulative histogram.

The correspondence of the Elo (left) and Dan/Kyu (right) scales is based on EGF assignments.

Rating histogram

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Data sources

AGA (American Go Association): http://usgo.org/ratings/RatingsQuery.asp - Ratings updated in or after 2005-11, as of 2007-11-6.
EGF/AGD (European Go Federation / Database): http://www.europeangodatabase.eu/EGD/
KGS (KGS Go Server): KGS Rank Histogram / Data
USCF: http://www.geocities.com/siliconvalley/lab/7378/histogra.htm

The raw data for KGS and USCF ratings are in the form of histogram buckets. I used linear interpolation to estimate more accurate numbers. The raw data for the AGA and EGF was the entire list, so I simply used the rating of the players at the appropriate percentiles.

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