Ian,
The topic of "fish METs" is an interesting one. I think that they can be
useful for non-contact race cubes, where humans can make precise
calculations over the board using race formulas. Beyond that, I'm a
little skeptical about how practical they are.
One thing that I feel that hardly anyone pays attention to is the fact
that two players with the same PR can have very different styles and make
very different kinds of mistakes. In today's PR-crazed world, there is a
strong tendency for most people to oversimplify and use just one number to
capture a player's backgammon ability. In reality, backgammon ability is
a multi-dimensional beast. In my own playing group, I know that one
player plays blitzes much too timidly, while another plays blitzes well
but has a strong tendency to break anchor too riskily. When I'm playing
one of these players and am assessing taking a blitz cube or offering a
holding game cube, I will definitely take into account my knowledge of
their individual playing weaknesses. It's quite possible that both
players have the same PR, in which case a fish MET might not distinguish
between them.
The fact that backgammon ability is multi-dimensional means that it's hard
to create credible fish METs with any degree of accuracy. If one tries to
cripple GNU by forcing it to make occasional random mistakes, one can
measure the PR of "crippled GNU", but this does not mean that crippled GNU
is a credible model of how a human (with the same PR as crippled GNU)
plays.
The Jacobs/Trice fish book is a wonderful book and an interesting proof of
concept, but I think that the above difficulties (among others) mean that
it's hard to actually apply the ideas in real life.
Tim
