10. 2012-S Improved Bonus Point Formula

[Lyle Craver]

Moved by Paul Leblanc
Seconded by Fred McKim

To replace the existing Bonus Point Formula (CFC Handbook Art. 714.d) with the following:

BONUS 1 = Rmax BONUS *a*Ke
BONUS 2 = b*RATING CHANGE BONUS*(Rnew – Rold – THRESHOLD)*Ke
TOTAL BONUS = BONUS 1 + BONUS 2

where:
a = 1 if the new rating is at an all time high, 0 otherwise;
b = 1 if Rnew > Rold + Threshold, 0 otherwise;

Threshold = RtgChangeThreshold*Ke*sqrt(n) where n is the number of games played; no bonus points are awarded if less than 4 games are played;

Ke is the ratio of the player's K factor to the K factor used for players rated under 2200; For the CFC rating system, K=32 for players under 2200 and K=16 for players at or over 2200;

Rnew is the post-event rating and Rold is the pre-event rating;
and RatingMaxBonus, RtgChangeBonus, and RtgChangeThreshold are constants with the following values:
RatingMaxBonus = 20; RtgChangeBonus = 1.75; RtgChangeThreshold = 13.

The numerical values in the bonus point equation may be adjusted from time to time by the Rating Auditor as deemed necessary and in consultation with the CFC Executive

Reason for Motion:

The proposed formula is based on detailed analysis of the existing tournament data base from 2006 to 2011 and is distilled from the examination of numerous options. It does a superior job of injecting rating points, i.e. when modelled, it generated ratings that more closely predicted actual game results than the existing system.

There were concerns that the existing formula awarded disproportionate bonus points to a small group of high rated players. The proposed formula improves this.

The rating system is inherently deflationary. Care was taken to select a formula that minimizes the effects of inflation and deflation.

The proposed formula mitigates the problem of under-rated juniors by awarding bonus points to players achieving new personal high ratings and by awarding a generous bonus to exceptional performances. These criteria are very common among juniors.

Detailed examination of the methodology leading to this proposal can be found at:

http://www.victoriachess.com/cfc/cfc_rating_doc.htm

[Bob Gillanders]

I have read through all the material, and I think I understand the formulas. But maybe I got it wrong. Could you please give us a few hypothetical cases, and calculate the bonus for us?

For instance, player X has the following result.

Pre tournament rating = 1500
Post tournament rating = 1550
games played = 6
Highest ever rating = 1525
All opponents <2000

Thanks.

[Egidijus Zeromskis]

A.
There are several math mistakes:
Rmax BONUS, RATING CHANGE BONUS - became RatingMaxBonus and RtgChangeBonus, etc.
That is not a scientific way to write down formulas and their explanations.

B.
Probably it is too late now but plots should include FIDE ratings.

C.
Still there are very huge jumps and downs.

D.
IMHO: No bonus points for players rated above 2199

[Kevin Pacey]

D.
IMHO: Bonus points should be applied only to 2200 players.

Part of the rationale behind this motion is to combat the effects of underrated juniors, presumably meaning largely juniors rated below 2200.

To take away bonus points from sub-2200 players would be contrary to this part of the rationale, which is one part I certainly agree has merit.

[Kevin Pacey]

D.
IMHO: Bonus points should be applied only to 2200 players.

IMHO, the CFC might consider eliminating bonus points for players rated above 2199, if we first pass the motion as is, and then find that rating inflation has resulted after some years. However I haven't a reason as yet to suspect that the modelling performed that helped produce this motion was incorrect.

[Egidijus Zeromskis]

eliminating bonus points for players rated above 2199

That what I wanted to write... Corrected.

[Paul Leblanc]

Fred McKim suggested in our discussions that players above 2400 not be eligible for bonus points. We decided to leave that discussion for this forum.
Egidijus, I'll make sure the variables are contracted/not contracted in the right places in the handbook/website. Is that your point about math errors?

[Paul Leblanc]

Bob, here is the answer to your question:

a) as player X's rating is <2200, Ke = 1.

b) Rnew is at a new high so BONUS1 = 20.

b) Threshold = 13* sqrt(6) = 13.84: => BONUS2 = 1.75*(1550-1500-31.84) = 31.78

c) Total bonus = BONUS1+BONUS2 = 20+31.78 = 51.78; Rounded to the nearest integer, this is 52 points.

Note 1: in Roger's work, the bonus calculation was rounded to an integer at the end rather than at an intermediate stage (although intermediate ratings used in the calculation, e.g. Rnew, were rounded when they were calculated)

Note 2: It doesn't matter that player X's opponents were rated below 2000.

[Egidijus Zeromskis]

b) Threshold = 13* sqrt(6) = 13.84

correct to 31.84

[Bob Gillanders]

Bob, here is the answer to your question:

a) as player X's rating is <2200, Ke = 1.

b) Rnew is at a new high so BONUS1 = 20.

b) Threshold = 13* sqrt(6) = 31.84: => BONUS2 = 1.75*(1550-1500-31.84) = 31.78

c) Total bonus = BONUS1+BONUS2 = 20+31.78 = 51.78; Rounded to the nearest integer, this is 52 points.

Note 1: in Roger's work, the bonus calculation was rounded to an integer at the end rather than at an intermediate stage (although intermediate ratings used in the calculation, e.g. Rnew, were rounded when they were calculated)

Note 2: It doesn't matter that player X's opponents were rated below 2000.

Thanks Paul. Threshold = 31.84, right?

I tried out the new formula on a recent tournament of mine, the Burlington Club Championship. I did well.

Old rating = 1819
new rating = 1872
games = 5
performance rating = 2092

No bonus points awarded under current system.

New proposed bonus plan
B1 = 0
Threshold = 29
B2 = 1.75 ( 1872-1819-29) = 42

Excellent. My new rating would have been 1914.

I like the new bonus system.