
BGonline.org Forums
Elo difference mapping to Snowie ER
Posted By: Timothy Chow
Date: Monday, 10 May 2010, at 3:38 p.m.
In Response To: Elo difference mapping to Snowie ER (Neil Robins)
There's some confusion here between the magnitude of the unit and the magnitude of someone's error rate.
Compare with physical weights. In terms of units, 1 kg = 2.2 lbs. Here the factor of "2.2" appears on the "lbs" side of the equation. However, if I give you my weight in pounds then you need to divide by 2.2 (not multiply) by 2.2 to get my weight in kilograms.
So when Rich said "PR ~ 1.1 ER" he meant that one's Snowie error rate should be multiplied by 1.1 to get one's XG performance rating. But in terms of units this should be written "1 unit of Snowie ER = 1.1 units of XG PR." So a difference of 1 Snowie ER should be a larger Elo difference than a difference of 1 XG PR, as Neil correctly calculates.

BGonline.org Forums is maintained by Stick with WebBBS 5.12.