I'm in favour of updating the classification; using the BMAB scales seems like a good measure.
The scaling of the PR values comes historically from Snowie, which used the sum of both players' moves as the divisor. Gnubg uses only the player's unforced moves, which naturally means gnubg error rates are at least double Snowie error rates. When XG was created Xavier calculated the error rates using the same method as gnubg, but then divided by 2 to scale them to the match Snowie Error Rate, which is what most people were familiar with. Gnubg error rate is more accurate as a measure of how many points your error will cost you, but we seem to have lost that battle in the public consciousness. I think it's time to drop Snowie Error rate from the statistics display, and replace it with PR. And if we do that, then we could use the BMAB ratings directly rather than re-scale them from PR to error rate. Cheers, Ian -----Original Message----- From: bug-gnubg-bounces+ian.shaw=riverauto.co...@gnu.org <bug-gnubg-bounces+ian.shaw=riverauto.co...@gnu.org> On Behalf Of Francesco Ariis Sent: Sunday, July 7, 2024 11:56 PM To: bug-gnubg@gnu.org Subject: Re: Skill level names Il 08 luglio 2024 alle 00:05 Philippe Michel ha scritto: > For the analysis results we could use the denominations from BMAB > (https://urldefense.proofpoint.com/v2/url?u=https-3A__bgmastersab.com_about&d=DwIDaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=DPylQUHTi_E0xrxfi9iWyIPcSxXPmeJo9B7gmdo99Oo&m=Jp51Qep4rYNDQKxKxouCkKOzFvJy-VbxX7PPthGwlTZt2NzNBoCRT0UZte1BgNE9&s=I17WfSVGEl2cGp1DQV0izGo6UXhVKyFG7shuQ845Rtc&e=) > without the 0/1/2/3 subdivisions: > error rate <= 5 Super Grandmaster > <= 8 Grandmaster > <= 13 Master > <= 20 Advanced > <= 32 Intermediate > else either Casual or Beginner This seems a very good idea, a set of recognisable titles that make sense for a human. I am a bit puzzled by some BMAB Level denominations though. If I read the table correctly, “Intermediate” lies between 10–16 PR. This should translate — again if I got it correctly — to a gnubg error rate of 20–36, which is “Beginner”/low “Casual Player”, the bottom of the interval being “Awful!” I guess that is some vanity sizing from the BMAB. But let this not be a blocker, the idea remains very good —F
