8.4.3.4 Overall rating
The last section is the overall summary.
 Error rate (total): The accumulated checker play and cube
decision errors reported by normalized and unnormalized.
 Error rate (per decision): The error rate per decision is
the total error rate divided by the number of nontrivial
decisions (i.e., the sum of unforced moves
and close or actual cube decisions). Again,
please note that is different from Snowie 4 that defines the
error rate per decision as the total error rate divided by the
total number of moves for both players. In general, your error
rate per move will be lower in Snowie than in GNU
Backgammon. An investigation of approximately
300 matches showed the on average the GNU
Backgammon error rate with be 1.4 times higher
than your Snowie 4 error rate.
 Equivalent Snowie error rate: For easy comparison
GNU Backgammon will also print the
total error rate calculated by the same formula as Snowie 4.
 Overall rating: Based on your normalized error rate per move
GNU Backgammon will assign you a rating ranging from
Awful! to
Supernatural. See the table below for the
thresholds.
 Actual result: The actual result of the game or match. For
money game this is simply the number of points won or lost
during the game or match. For match play the number is
calculated as 50% added to the result of the game or match in
MWC. For example, losing a match or winning a match corresponds
to an actual result of 0% and 100%, respectively. Winning 1
point in the first game of 7 point match is worth 6% using Kit
Woolsey's match equity table, hence the actual result is 56%.
 Luck adjusted result: The luck adjusted result is calculated
as the actual result plus the total
unnormalized luck rate. This is also called variance
reduction of skill as described in Douglas Zare's
excellent article Hedging Toward Skill. This should give an unbiased measure of
the strengths of the players.
 MWC against current opponent: For match play
GNU Backgammon will calculate your
MWC against the current opponent. The number is calculated as
50%  your total unnormalized error rate + your opponent's total
unnormalized error rate. If your opponent is really lucky but
plays rather bad, this number can become larger than 100%, since
he due to the extra luck has the possibly to give up even more
MWC. However, GNU Backgammon will
report this number as 100%, and 0% for the opposite situation.
Note that this number is biased towards the analyzing bot, e.g.,
a 0ply analysis a game between GNU Backgammon 2ply and 0ply
will suggest that 0ply is a favorite, which it is clearly not.
For an unbiased measure use the luck adjusted
result above.
Threshold for ratings:
Normalized total error rate per move  Rating

0.000  0.002  Supernatural

0.002  0.005  World Class

0.005  0.008  Expert

0.008  0.012  Advanced

0.012  0.018  Intermediate

0.018  0.026  Casual Player

0.026  0.035  Beginner

> 0.035  Awful!

Please note: The Normalized total error rate per move is
multiplied by 1000 in the default settings.