What the H is 0 EV?

[luckyme]

I'm asking this in the math/philosophy forum because it appears the situation we call 0EV may be arbitrary, and I'm looking for clarification.

As I understand it's use in most poker situations we seem to consider folding ( or checking last) "you stack doesn't change from the moment of choice of action" as the base ... 0 EV ?

Perhaps in non-poker situations it's more difficult to agree on what the 0EV choice is.
1) if I decide not to go to work today. Is that a -EV choice or the 0EV choice ( just taking earnings into account).
2) this arose in the 'Deal or No Deal' thread - is taking the deal the 0EV choice, or is it +EV or -EV depending on it's comparison to your expectation if you continue with the gamble. ( ignoring Utility or shifting V).
3) A promo tv show offers you a coin-flip for your car. You win you get another one plus $1000, you lose, you lose your car. Is refusing to play 0EV or -EV.

I arrived at the 0EV choice being -
1) not going to work.
2) taking the deal.
3) refusing to play.

but I'm asking ... luckyme

[madnak]

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1) if I decide not to go to work today. Is that a -EV choice or the 0EV choice ( just taking earnings into account).

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You still have daily expenditures, so it's -EV.

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2) this arose in the 'Deal or No Deal' thread - is taking the deal the 0EV choice, or is it +EV or -EV depending on it's comparison to your expectation if you continue with the gamble. ( ignoring Utility or shifting V).

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Once you have the deal taking it would be 0 EV. Gambling would be + or - EV based on expectation. When the deal is offered you have the guarantee of that amount of money. Of course, going into the show and getting a deal is +EV overall.

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3) A promo tv show offers you a coin-flip for your car. You win you get another one plus $1000, you lose, you lose your car. Is refusing to play 0EV or -EV.

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0EV, but it depends on the context again. You can make a -EV choice in a poker game and still expect to win the pot. 0 EV is really arbitrary, you can choose to put it anywhere. If 0 EV is winning a large pot, then you'll be choosing the least -EV option instead of the most +EV option, but it's the same option either way.

It's like how you can measure temperature starting from absolute 0, or starting from freezing temperature. Either way is valid, but the actual temperature is of course not going to change based on which scale you use.

[madnak]

I'd like to make a clarification. I'm saying that it's the relationships between the expected values of different actions that matter, not how the EV values are described.

[luckyme]

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I'm saying that it's the relationships between the expected values of different actions that matter, not how the EV values are described.

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Yes, that seems true about what matters.

A recent thread, where everyone understood the probabilities of the outcomes, had one outcome referred to as -EV, OEV and +EV. It doesn't add to the clarity of the exchange :-)

I was wondering if there was a fairly standard approach to attaching 0EV to one outcome. Maybe I'll just have to learn to live with uncertainty,

thanks, luckyme

[madnak]

I think a standard can be determined for specific kinds of situations. It's definitely possible to define "0 EV" in terms of poker, for example.

But in life there are so many variables and so many scales of value and so many different ways of looking at things that I don't believe a general "overall" standard for how to evaluate 0 EV is possible. I think it becomes a kind of "glass half-full or glass half-empty" situation.

[luckyme]

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But in life there are so many variables and so many scales of value and so many different ways of looking at things that I don't believe a general "overall" standard for how to evaluate 0 EV is possible. I think it becomes a kind of "glass half-full or glass half-empty" situation.

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Hey, "it is FULL".. half-air, half-water.

I've been assuming the OEV was from a 'frozen in the moment' take on things, but the various uses of it have sensitized me. Now I'm afraid to use the term without a definition.

thanks,m, luckyme

[chezlaw]

you got me confused. Doesn't the V in ev has to represent a number that is ordered.

When you are evaluating evs you're putting a value on V for each of the possible option and its the decisions that are 0ev, +ev or -ev. For simplicity lets look at a binary decision.

If you have two choices A or B then work out Va and Vb.

Choosing A or B is a 0ev decision if Va=Vb.
If Va>vb then choosing Va is +ev and chosing Vb is -ve.

chez

[luckyme]

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If you have two choices A or B then work out Va and Vb.

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Ah. I've always looked at it as (EV)a and (EV)b. You fill out a financial statement prior to taking any action and then compare that ( the OEV base) to the position(s) you'll be in after various actions.
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If Va>vb then choosing Va is +ev and chosing Vb is -ve.

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ah. I thought if they both improved your present state then they'd both be +EV, just that one would be greater.

Looks like Madnak had it pegged --
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Either way is valid, but the actual temperature is of course not going to change based on which scale you use.

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thanks chez, it does look like there is no 'standard' way of referring to EV. luckyme

[chezlaw]

A long as we're consistent then there's many ways of looking at it.

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Ah. I've always looked at it as (EV)a and (EV)b. You fill out a financial statement prior to taking any action and then compare that ( the OEV base) to the position(s) you'll be in after various actions.

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So you can do that without any problem but it could be misleading because it seems to imply that doing nothing is an option which it may not be or not.

It just seems clearer (maybe just to my wierd mind) to evaluate the decisions relative to each other.

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ah. I thought if they both improved your present state then they'd both be +EV, just that one would be greater.

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Yeah, that's common and I hate it /images/graemlins/smile.gif

chez

[luckyme]

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So you can do that without any problem but it could be misleading because it seems to imply that doing nothing is an option which it may not be or not.

It just seems clearer (maybe just to my wierd mind) to evaluate the decisions relative to each other.

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If OEV is simply the 'present state' there is no need for it to be a stable state. It doesn't have to exist as one of the choices.

Your weird mind actually seems natural (this time :-). If I have $10000 in my mattress and one bank offers me 5% interest to deposit it and the other 2%, I tend to think of the 2nd choice as "losing" 3% not gaining 2.

I do think standard EVspeak would treat them both as +EV.

thanks for your comments, chez. luckyme