H Francesco. XG PR, Snowie Error Rate, and GnuBg Error Rate are all based on measuring the normalised error, although they have slightly different implementations.
Snowie: (Your total errors) / (number of moves by both sides) Gnubg: (Your total errors) / (number of your unforced moves) Because gnubg uses only one side's moves in the denominator, gnubg error rates will be about double the Snowie error rate. When XG was written, the creator thought that Grub's implementation made more sense, but he wanted to have error values that were broadly equivalent to Snowie, because it was what most people were familiar with. So, PR is a compromise: PR: (Your total errors) / (number of your unforced moves) * 2 The *2 multiplier scales gnubg error rate into values that are recognisable to Snowie users. People fixate on PR because minimising errors is the surest way to improve your game. However, there may be situations where you want to take your opponent into account, leading you to choose a different option. It's very easy to over-adjust, though, because you are relying on your opponent to make enough mistake to overcome the equity you have deliberately sacrificed. Regards, Ian -----Original Message----- From: Francesco Ariis <fa...@ariis.it> Sent: Thursday, June 6, 2024 8:33 PM To: Ian Shaw <ian.s...@riverauto.co.uk> Cc: bug-gnubg@gnu.org Subject: Re: Error rate and Luck adjusted result Hello Ian, Il 06 giugno 2024 alle 11:10 Ian Shaw ha scritto: > Error rates are "normalised". That is, they are adjusted to make them > all match the size that the error would be if you were playing a money > game and the cube were at 1. > > Luck takes into account the match score. For example, a lucky 66 makes > a much bigger difference to the overall result of the match if comes > in a bearoff at double match point rather in game 1 of an 11 pointer. many many thanks, this gives me a much clearer picture, I did not know about normalisation. Now that I understand it, I think people online fixate too much on PR (which I believe it is similar to what gnubg outputs as “Snowie error rate”). Thanks again —F
