From: Ross Dickson <rdickson <at> ACHILLES <dot> NET>
Date: 1 jun 2003
Subject: Re: Dual ratings

It is with some trepidation that I present the least mean square results
for the enlarged data set Larry has produced.

Pan-Atlantic = 0.6 times ShogiClub24 + 1100 is a close approximation to the
linear regression (lms slope = 0.5962 , lms intercept = 1118.7).

The original data is in the first two columns, sorted in order of
SHogiClub24 score, the calculated Pan-Atlantic follows, and then the
difference between the calculated and Actual values of the Pan Atlantic
scores.

Actual   Shogi    Calc     Actual
PanAtl  Club24    PanAt    - Calc
2422,    2284,    2485,      -63
2455,    2118,    2386,       69
2255,    2013,    2323,      -68
2285,    1993,    2311,      -26
2174,    1925,    2270,      -96
2195,    1753,    2167,       28
2094,    1555,    2049,       45
1980,    1513,    2024,      -44
1660,    1507,    2020,     -360
2118,    1455,    1989,      129
2101,    1465,    1995,      106
2012,    1453,    1988,       24
1926,    1378,    1943,      -17
1852,    1377,    1942,      -90
1973,    1312,    1904,       69
1809,    1298,    1895,      -86
2044,    1181,    1825,      219
1908,    1161,    1813,       95
1599,    1157,    1811,     -212
1769,    1149,    1806,      -37
1924,    1124,    1791,      133
1827,    1091,    1771,       56
1791,    1072,    1760,       31
2074,    1064,    1755,      319
1784,     993,    1713,       71
1772,     933,    1677,       95
1620,     797,    1595,       25
1272,     789,    1591,     -319
1505,     635,    1499,        6
1138,     336,    1320,     -182

The large (and possibly periodic) deviation of a number of points is
interesting. Perhaps the starting rating does have some effect.

Ross


<<The following is an updated listing of all ratings of players rated on
both the Pan-Atlantic and ShogiClub24 rating systems fulfilling the
criteria given below.

       2455    2118
       2422    2284
       ...     ...
       1272     789
       1138     336

     All players listed have at least 80 games on ShogiDojo, which reduces
the effect of starting rating to under 5%.  All players listed have at
least 24 games on Pan-Atlantic (16 for kyu players), where starting rating
plays only a tiny role and is in any case based on known rank.  Player must
be listed on 2002 or 2003 Pan-Atlantic rating list.  No names are given in
case some players prefer anonymity.
     There are 30 players on this list, eleven more than last time.  Six
are kyu players.  Hopefully this will give us a much more meaningful
conversion formula.

     Larry Kaufman>>