Re: RE: [Bug-gnubg] Removal of absolute fibs ratings

[Massimiliano . Maini]

Another funny thing wrt to FIBS ratings : it seems to me that when playing
1-pointers the FBS rating is much more severe (compared to the error rate
based "overall rating") than when playing longer matches.

Example :

1) 1-pointer
Error rate (total) :                -0.111
Error rate (per decision) :         -5
Equiv. Snowie error rate  :         -2
Overall rating :                    World class
Error based abs. FIBS rating :      1890.8

2) 15-point match
Error rate (total) :                -0.695
Error rate (per decision) :         -5
Equiv. Snowie error rate  :         -2
Overall rating :                    World class
Error based abs. FIBS rating :      2004.3

3) 1-pointer
Error rate (total) :                -0.256
Error rate (per decision) :         -11
Equiv. Snowie error rate  :         -5
Overall rating :                    Advanced
Error based abs. FIBS rating :      1668.3

[I've no example of a long match where I played -11/Advanced, but I'm
sure that in a 5pt match, when you get Advanced you normally get a FIBS
rating of 1900 or more].

Maybe there's just a bug in the computations, possibly due to absence
of cube. Another possibility is that Kees' formula somehow incorporates
a correlation between chequer errors and cube errors, which would make
the frmula not adapted to 1-pt matches.

Any thoughts ?

MaX.