Alpha and MDF Revisited
Hi, I am new to poker and I am reading "Modern Poker Theory" by Michael Acevedo. There is a section called "Alpha and MDF Revisited" that says:
"EV has to be compared between all the different actions a player can take and never in a vacuum. I’ve seen many top players, and even famous poker coaches, making the mistake of using the Alpha Number and MDF to justify making bad plays. The discussion often goes something like this:
“My flop bet is profitable, it only has to work X% of the time and the Villain is folding more than that, therefore I’m making money!”
While that statement might be true, we cannot forget where Alpha and MDF numbers come from. They are derived from the EV equation. They assume that the EV of checking back your hand is 0 and that every time you are called and hold a bluff that you lose the pot and your bet. However, on the flop most poker hands will almost always have some equity as even the worst hands can improve on future streets. For this reason, the Alpha and MDF numbers are misleading. In reality, the BB does not have to defend nearly as many hands as MDF suggests, because they do not have to make IP’s worst hands indifferent to 0. IP has to make them indifferent to the EV of checking back. Also, IP won’t always lose the entire pot when they are called and hold a bluff because sometimes this bluff will pick up equity which makes the continuation bets more profitable than expected."
I am really stuck at the red-colored part. Anyone mind explaining to me in detail what this means? Much appreciated!
2 Replies
Hi, I am new to poker and I am reading "Modern Poker Theory" by Michael Acevedo. There is a section called "Alpha and MDF Revisited" that says:
"EV has to be compared between all the different actions a player can take and never in a vacuum. IÂ’ve seen many top players, and even famous poker co
I'll take a shot at explaining but there are others who could probably do better.
Take a situation where, e.g., you open the button and get called by BB. BB checks flop and you bet 1/3 pot.
If BB folds more than 25% of the time your bet yields instant profit. Thus, one could justify (incorrectly, according to Acevedo) betting potentially any hand on the grounds that you're confident villain will fold more than MDF (25% in this case).
However — this is the critical point — this alone does not mean that betting is necessarily a better play than checking. If villain folds more than MDF your bet will be profitable, yes — but not necessarily more profitable than checking back. Villain overfolding makes the bet +EV, but this needs to be compared with the EV of checking. From Villains perspective, therefore, overfolding relative to MDF is fine, so long as he's not folding so much that hero's bet (with his worst hands) becomes higher EV than checking.
This is what is meant by making IP's worst hands indifferent to the EV of checking back, as opposed to indifferent to 0 (which is how alpha and MDF are calculated). In short, the MDF taken alone is insufficient to determine the best play, and therefore cannot alone justify any given play. Exceptions can occur in polarized river situations where the implicit assumptions of the MDF calculation are valid — the EV of checking back is 0, and every time you're bluff is called you lose the pot.
Imagine you open on the button and the big blind calls. (BTNvBB SRP)
You go to the flop and the BB checks. You are the button and now have two choices:
1. Bet
2. Check
You want to choose which option is best... even if bet is > 0 EV, checking might be higher EV than bet.
The excerpt you put in the OP is correctly stated and accurate.
