JLahrman,
Interesting analysis, but I am not sure I follow completely. I take it that the main concern was winning the match not the hole, and it sounds like A was dormey. B needed to make the putt and have A miss to win the hole and square the match. If A makes, A wins the match regardless. If B misses, A wins regardless regardless.
Odds of B tying match if A putts are the chance of A missing times chance of B making. 24/25*1/15 = 8/125 = 6.4%
Odds of B tying match if A doesn't putt are 1/20 = 5%
So from a statistical standpoint only, A should pick up. Shouldn't he? Or do I have something wrong?
I didn't make the dormie assumption from Jim's post.
But if the match is dormie, then yes I agree with you, A should pick up purely from a statistical standpoint. A could obviously win the match by making the putt, but the problem is that A is not likely to make the putt, and if we figure that B's chances of making the putt go from 1 in 20 to 1 in 15 purely from seeing the putt happen, then yes A should pick up.
That's why it a question of risk tolerance. Pick up and the odds that hole is halved are 95%, but the 5% is all upside for B.
If A putts, the chances of halving the hole are down to 89.9%. There is now a 3.7% chance that A wins the hole, and a 6.4% chance of B winning the hole.
But in a dormie match, halving the hole and A winning the hole are the exact same thing. If A putts, he's lowered his chances of finishing off the match from 95% to 93.5%. But if you were on the third hole of the match, A would probably figure it's worth accepting the risk of giving B a read in order to give yourself the chance to win the hole.