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XG's "best choice"

Posted By: Ray Kershaw
Date: Sunday, 26 July 2015, at 1:47 p.m.

When the correct cube action is no double / take, XG provides a "best choice" percentage. I interpret this as the probability that your opponent will pass which makes it correct to double. But I can't follow how XG calculates this.

For example,in this last roll position, with no Jacoby Rule, XG gives "best choice" as 19.0%. But I think this should be 23.5%. If I get a pass 23.5% of the time for a win of +1 and a take 76.5% of the time with an average loss of -0.889, then on average my loss after doubling is -0.444, the same equity as when I do not double.

Can one of the experts here explain where I go wrong?

 is Player 2 score: 0 pip: 1 Unlimited Game pip: 9 score: 0 is Player 1
XGID=----AA------------------a-:0:0:1:00:0:0:0:0:10
on roll, cube action?

 Analyzed in XG Roller++ No double Double/Take Player Winning Chances: 27.78% (G:0.00% B:0.00%) 27.78% (G:0.00% B:0.00%) Opponent Winning Chances: 72.22% (G:0.00% B:0.00%) 72.22% (G:0.00% B:0.00%) Cubeless Equities -0.444 -0.889 Cubeful Equities No double: -0.444 Double/Take: -0.889 (-0.444) Double/Pass: +1.000 (+1.444) Best Cube action: No double / Take Percentage of wrong pass needed to make the double decision right: 19.0%

eXtreme Gammon Version: 2.19.208.pre-release

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