Calculating EV
Hi Guys,
Let's say I have AA and villain has KK. So I have roughly 80% vs 20%. Pot is 100 and we both have 100 behind.
1. Villain goes AI (100)
2. Hero call 100.
EV calculation would be 80%*200 - 20%*100 if I am not mistaken.
But what I am wondering is how do you calculate EV if:
1. Villain bets 20
2. Hero raises to 40
3. Villain raises to 100
4. Hero calls 100
Now, do I calculate EV exactly the same as before, or should I start calculating EV from action 3, for example:
At action 3 pot is now 160 (100 + 20 + 40).
Villain adds 80 (making pot 240) and I have to call 60.
So, EV = 80%*240 - 20%*60
What is the correct way?
2 Replies
Your equation is correct.
EV is defined as the change in your stack as a result of the current decision and is equal to the amount you expect to win less the amount you expect to lose. The money in the pot you contributed in past actions now becomes potential winnings.
Actually, instead of using the stack at the last decision point as the baseline, you can use other baselines for determining stack change, such as the stack at beginning of the hand. But you must then use the same baseline for all decision options such as call, raise or fold. When comparing EVs for determining the best decision all baselines will suggest the same best.
I should have mentioned that your example stated the villain made an all-in bet. If not, then an equity estimate such as provided by the Equilab poker calculator is a showdown equity, so the equation is exact only if the hand is checked down. Otherwise, the EV equation as written above only provides a first cut EV approximation. With future betting and a possible fold, things get more complicated and equity realization becomes a major factor along with the changes to the amounts to be won and risked.
