All-in Breakeven Points

[kevkev60614]

Bored and messing around with ICM. If you operate under a few assumptions, it becomes easy to see why taking coinflips in a SnG is a bad idea, particularly as the end nears.

Assumptions:
All players have equal stack sizes.
All players are of equal skill level.
Blinds are negligible.
This manner in which this hand is played out will not effect future hands.

To breakeven in $EV, if a player goes all-in and you call, you have to win over 50% of the time, as shown below.
If calling and winning will eliminate the 10th player, you need to win 54.2% of the time to breakeven.
9th - 54.8%
8th - 55.6%
7th - 56.6%
6th - 58.1%
5th - 60.6%
4th - 65.2%
3rd - 76.9%
2nd - 80.0%

Relaxing the first assumption:
If Hero and Villain have the same stack sizes, but other players don't, these percentages increase. The presence of a short stack puts you further ahead before the coinflip, and in essence you're gambling with more money.

If Hero has more or less chips to begin with, these percentages decrease.

If Villain has less chips to begin with, these percentages decrease. If Villain has more chips to begin with, these percentages increase.