USCF Rating for International Tournaments

Running Chess Tournaments
1

It appears to be USCF policy to rate certain international tournaments that our players attend. At question is the formula used to convert from one rating system to the next.

When this issue came up previously, the topic was the World Youth Festival. The players were typically underrated juniors with a USCF rating much higher than their FIDE, much above the 50 point average difference. We saw some players who gained significant points FIDE but, at the same time, lost points USCF. We saw another player who brought home a gold medal, going perfect against players under 2250 and earning 33 FIDE points, but gaining a measely 7 points USCF.

The explanation given was the discrepancy in rating for these players, many who had a much higher USCF rating than FIDE rating. While the average player has a USCF rating of about 50 points higher than their FIDE rating, some kids had a difference of 100 or 150 points. While mathematically the calculations make some sense, I’m not sure this is the right approach to this problem considering the underrated nature of the young players.

Now I wish to point to the Moscow and Aeroflot Opens.
uschess.org/msa/XtblMain.php?200802025891
uschess.org/msa/XtblMain.php?200802145901

Moscow Open:
Friedel 2531 -8 USCF and 2487 -5 FIDE
Pruess 2497 -15 USCF and 2431 -9 FIDE

Aeroflot Open:
Friedel 2523 -7 USCF and 2487 +4 FIDE
Pruess 2482 -18 USCF and 2431 -19 FIDE

Who here can explain how Friedel can gain 4 FIDE points and lose 7 USCF points in the same tournament. Furthermore, how can he lose 5 FIDE points in the first tournament and gain 4 FIDE points in the second, but the USCF change for the same two events is -8 and -7? The net difference for Friedel was -1 FIDE but -15 USCF.

Likewise, Pruess did almost equally poorly in terms of USCF rating for both tournaments, but FIDE had a much larger difference. I can see how players who have different USCF/FIDE ratings might gain or lose more points than the other, but this time we’re talking about the same player!

Please observe that both Friedel and Pruess have USCF and FIDE ratings close to the 50 point average difference, unlike the kids discussed before.

Michael Aigner

2

Adjusting USCF ratings for play in non-USCF rated FIDE events goes back a while. This practice was reinstated by the Board several years ago and was recently enhanced to comply with the Board’s discussion on this issue at the November 2007 meeting. Randy Hough, who volunteered to do this at the November EB meeting, did most of the work to prepare the roughly 60 adjustments that were posted before running the June ratings list.

Here’s the writeup on the current policy:

You can use the conversion formula in the PDF listed above and the ratings estimator program on the website to see how the adjustments were computed. When someone’s USCF rating is well above or below the equivalent FIDE rating, adjustments that go in one direction for FIDE ratings and in the other direction for USCF ratings are still possible.

3

Thank you Mike for the conversion formula. I’ll demonstrate the calculations by hand for Friedel in the Aeroflot Open.

Friedel’s FIDE rating = 2487 → converted to USCF = 2523
His actual USCF pre-tournament rating was 2523!
His final score was 5.5/9. He gained 4 FIDE rating points.

formula: USCF = FIDE + (FIDE-2200)/8 for FIDE ratings between 2200 and 2600

Opponents:
Potapov, Pavel 2395 RUS 0.5 → converted to USCF = 2419
Dashibalov, Erdem 2408 RUS 1 → converted to USCF = 2434
Ter-Sahakyan, Samvel 2369 ARM 1 → converted to USCF = 2390
Kacheishvili, Giorgi 2544 GEO 0.5 → official = 2644 USCF
Vorobiov, Evgeny E. 2537 RUS 0 → converted to USCF = 2579
Wan, Yunguo 2389 CHN 0 → converted to USCF = 2413
Okara, Andrey 2402 RUS 0.5 → converted to USCF = 2427
Kaplan, Sasha 2456 ISR 1 → converted to USCF = 2488
Mihajlovskij, Sergei 2466 BLR 1 → converted to USCF = 2499

I plugged Friedel’s pre-tournament USCF rating of 2523 and the nine converted USCF ratings for his opponents into the ratings calculator. I got: performance = 2558, new rating = 2529 (+6). Since Randy Hough says that the USCF adjustment should be only 80%, Friedel’s USCF rating should have increased 5 points for Aeroflot Open. Instead, it decreased by 7 points. What gives?

Michael Aigner

4

I went back to the file Randy sent me, there are some differences between the converted ratings he used and the ratings you used for the Aeroflot event. Also, it appears Randy is showing Friedel as having scored 5.5 but the detail above that adds up to only 5 points A score of 5.5 appears consistent with what you entered.

How all that comes up with a loss of 7 points is something I cannot explain.

Randy will have to review his data to see what corrections are needed.

5

Friedel did score 5.5 points (four wins and three draws) against 9 FIDE rated opponents.

Michael Aigner

6

Randy shows 5.0 points in the detail and 5.5 points in the summary, I don’t know which he used when computing the adjusted rating, nor can I explain the difference in converted ratings.

I’m writing Randy to suggest he review that data for corrections.

7

With the questions about the entire USCF/FIDE rating issue, I went back to look at Daniel Naroditsky’s result at the World Youth Festival. He gained +33 FIDE but merely +7 USCF, a number that his father and I thought should have been 15-20 points.

Naroditsky’s FIDE rating = 2124 → converted to USCF = 2124
His actual USCF pre-tournament rating was 2234.
His final score was 6.5/8 against rated players and 3.0/3 against unrateds.
He gained 33 FIDE rating points.

formula 1: USCF = FIDE + (FIDE-2200)/8 for FIDE ratings between 2200 and 2600
formula 2: USCF = FIDE for FIDE ratings below 2200

Heung, Christopher 1863 USA 1 → official = 1980 USCF
Iskandarov, Misraddin 2031 AZE 1 → converted to USCF = 2031
Srbis, Jurica 2055 CRO 1 → converted to USCF = 2055
Nyzhnyk, Illya 2377 UKR 0.5 → converted to USCF = 2399
Bajarani, Ulvi 2268 AZE 0 → converted to USCF = 2277
Idani, Pouya 1853 IRI 1 → converted to USCF = 1853
Nakauchi, Gene 2040 AUS 1 → converted to USCF = 2040
Bukavshin, Ivan 2248 RUS 1 → converted to USCF = 2254

I plugged Naroditsky’s pre-tournament USCF rating of 2234 and the eight converted USCF ratings for his opponents into the ratings calculator. I got: performance = 2415, new rating = 2253 (+19). Since Randy Hough says that the USCF adjustment should be only 80%, Naroditsky’s USCF rating should have increased 15 points for World Youth. Instead, it increased less than half of that, merely 7 points.

8

Perhaps whatever Randy was doing wrong, he was doing CONSISTENTLY wrong?

The writeup I posted is something I put together last week, it was reviewed by Bill Goichberg, so I’m assuming it accurately reflects what was supposed to be done.

There were 68 adjustments from FIDE events made ahead of running the June list, from 38 different events (FIDE considers each section of an event a different event.)

Would you like the complete list so you can review all of Randy’s work? I’ve emailed him, I have not yet heard back from him.

9

I can. And, I suspect you can, too.

10

Based on a note from Randy Hough, Josh Friedel’s adjustment in the Aeroflot event has been changed from -7 to +4. A one point change (from +6 to +5) was also made for an event Boris Gulko played in.

Both of these changes should be posted after Tuesday’s rerate pass .

BTW, Naroditsky’s adjusted rating from the World Youth was computed using the old formula (back in March, I think), not the most recent (game by game) one, because he did qualify for that formula at the time.

So far nobody has suggested that we retroactively change any of the previously made adjustments, and I’m not sure who’d do the work gathering the data should someone make that suggestion.