equity based on # of opponents

[pariah]

I was playing around with PokerStove today comparing certain hands & how they fare depending on the number of opponents. As expected, hands like 87s did better as we added players and something like 22 did worse and worse.

What I don't understand is the difference between AA heads-up and 3-way. HU it's +35.2% but with 2 opponents it jumps to +40.3% and doesn't drop under +35% until there are 5 opponents. Shouldn't AA do worse as we add players?

What am I missing here? Please don't flame me, I'm terrible with math and just trying to figure this out.

[rufus]

It depends on what you're calculating. A fundamental shortcoming of percentages is that they're dimensionless -- they don't telly you what's being measured.

Now, if you're calculating EV as a percentage of bet:
(expected money back)/(money bet)
then adding more players can increase the value. (This quantity EV to the value of putting a dollar in the pot.)

On the other hand if the percentage is:
(hands won)/(hands played)
The adding more players will decrease the value. (This quantity translates to the value of dollars already in the pot.)

I expect that pokerstove is calculating the former value, since aces are a slight dog to win against 5 opponents, but that doesn't really make sense either (unless you're restricting the opponent's range of holdings).