1-18-06 [poker]For review, a "stop n go" is something like this : you're on a medium stack, perhaps M = 7 or so. The button raises, and you have a hand like 88. You could just push here, but you think he either has a pair or overs, and he's certainly calling preflop, so you have zero fold equity. Rather than just pushing and racing, you just call his raise, and push any flop. Now, consider some flops. Let's say an ace hits on the flop. He will now certainly call with an ace, and you're dead. He'll fold any hand without an ace, such as KQ, and also 99 and 77. So, pairs that beat you will fold, as will hands you're beating anyway. What if the flop is all low? He'll fold any high cards that missed (probably, unless your stack is uber low and he still has odds to call with good high cards), and call with any pair.
Consider a specific case. He raised to N and you have 3N chips. You just call and push the flop for the rest of your stack, which is now a pot size bet. He has two overs. He hits a pair on the flop about 31% of the time. He'll call with a pair and fold without. If you just pushed preflop, he'd call and you'd be a 55/45 favorite. Either way you're getting all your chips in, so we'll just look at your expected stack in either case.
Just push : EV = 0.55 * 6N = 3.3N Stop n Go : if he hit a pair : you still win 8.8 % of the time : EV = 0.088 * 6N = 0.53N if he missed his pair, he folds and you win +N EV = 4N net EV = 0.31 * 0.53N + 0.69 * 4N = 2.92N
So, the Stop N Go is a -EV move. Also, in this form it's really irrelevant that you have a hand like 88, since really you're just purely bluffing.
I like the Stop N Go a lot better when you have AK, or AQ if you're desperate. In this case you put your opponent on a low pair. If you push, he'll call and you race as a dog. If you wait and see a flop, maybe you hit your overs, if not, you push anyway. If he has overs, he folds, and if he has a low pair, he still might fold if there are decent overcards, like QJ if you have AK, etc.