Re: [Bug-gnubg] Re: The importance of METs

[Robert-Jan Veldhuizen]

At 12:01 9/12/2003 -0400, Albert Silver wrote:

> I'd like to reiterate my suggestion of testing
> the METs specifically at the scores where they differ the most. Zare
> pointed out that the Woolsey table at 4-away 3-away looked completely
> wrong compared to the Snowie table for example. Many othger scores may
> be quite correct so testing all the scores may dilute the differences
> one would feel. How about trying a series of match games where the score
> is specifically 4-away 3-away and see how big a difference it makes?

I think what you're proposing here might exactly be the reason why 
different METs make so little difference overall.

If Woolsey's MET is specifically flawed for (-4,-3), you can't test the 
effect of that by playing this matchscore! No checker play or cube decision 
will need this equity; only entries "higher up" in the MET will be used to 
make decisions.

So, the MWC of (-3,-4) are only relevant at scores further away than that, 
and these can be many different scores! You'd basically have to test many 
matchscores where the (-3,-4) MWC has a significant effect to the outcome. 
So you might have to test (-3,-5), (-3,-6), (-3,-8) and (-4,-4), (-5,-4), 
(-7,-4) f.i.

Even then, the outcome of these games will be mostly due to the dice 
rolled, and just very rarely because one MET causes a different decision to 
be made than another. And even then, the difference will probably be small.

Altogether, for MWC at the START of a match based on two different METS 
used by the players and other things equal,  there will be very little 
difference as long as the MET used are not clearly unreasonable.

Still, (creating) a good MET is interesting and important, because in 
(many) SPECIFIC positions at certain matchscores, it can make quite a big 
difference (like 0.1 EMG).

Cheers,


--
Robert-Jan Veldhuizen