Theory question: How many lines are "off"?

[BobJoeJim]

Obviously, the ideal of sports betting would be to bet the +ev side of every game that offers a +ev side, while staying away from "correct" lines where the juice makes both sides -ev. My question, which I'm not sure is quantitatively answerable, but that I do think is interesting, is: What percentage of lines are accurate enough that the juice makes both sides -ev, and what percentage of lines are profitably bettable (if you can identify the correct side to take)?

Obviously this will vary from sport to sport, so for the sake of this discussion let's focus on football sides and totals (not moneylines, let's keep it to the "50/50" bets). I'm curious to hear people's thoughts on this.

If you're curious what got me thinking about this in the first place, it was a combo of my not finding a play I liked when I analyzed the Rutgers/USF game (since I'm trying to analyze every "only game of the day"), and Assani's threads where he handicaps every NFL game. Basically, another way to put this question is: if you trust your abilities as a handicapper, and you analyze every single game each week, and are willing to take any edge, no matter how small, what percentage of the games should you probably be placing bets on? Let's assume -110 juice on all the games, again just for consistency's sake (though if you want to discuss how the percentage would increase as the juice decreased, that could also be an interesting topic. I'd like to hold it off at first, though, because it's sort of level two of this question, along with the effects of line shopping, and I'd like to focus on level one first.)

[smbruin22]

i think you're basically asking "what % of lines are completely wrong?"....

but then i'm not sure if florida is 10 point favorite, but loses by 10, if that line was "wrong" or simply variance/circumstance/injury etc.....

here's what i'd like to know: how often do you see lines that you think are "easy money"??....two that come to mind are the UNDER on that early FSU/Miami and the point spread when miami and nebraska played for national title.

[Performify]

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if you trust your abilities as a handicapper, and you analyze every single game each week, and are willing to take any edge, no matter how small, what percentage of the games should you probably be placing bets on?

[/ QUOTE ]

My $0.02:

For NFL football sides, I do this: I analyze every game each week and pick at anything over a certain threshold of edge.

For my "system" I find about half of the NFL action in a given week differs in a statistically significant way from 50-50 - say seven games a week - and i'd say only three to five of those are measurably off (i.e greater than 52%) enough to warrant action. Sometimes more games are "off", more often less.

Note that I do not include totals in any of this, this is just sides.

[BobJoeJim]

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i think you're basically asking "what % of lines are completely wrong?"....

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I would think of "completely wrong" as meaning there is a large edge, such as a 60% chance or better of one side hitting. This is more than enough to beat the juice. What I'm asking is how many are just off enough that one side has a 52.5% chance of winning? It's a small edge, and of course finding it is a completely seperate issue, but how often is it there, versus how often a line really is 50/50?

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but then i'm not sure if florida is 10 point favorite, but loses by 10, if that line was "wrong" or simply variance/circumstance/injury etc.....

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This is of course why this question can't have a definitive answer. Even knowing results, there's no way to tell which lines were +ev with any certainty.

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here's what i'd like to know: how often do you see lines that you think are "easy money"??....two that come to mind are the UNDER on that early FSU/Miami and the point spread when miami and nebraska played for national title.

[/ QUOTE ]
I would consider this to be the question "What percent of lines are completely wrong," not what I originally asked. It is a good question, though, and worth adding to the discussion.

I will say that as of now I have no specific thoughts as to what the answer is, I was asking this as a genuine question to get the opinion of people with more experience than me, not as a prelude to telling you all my thoughts on the subject.

[smbruin22]

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I will say that as of now I have no specific thoughts as to what the answer is, I was asking this as a genuine question to get the opinion of people with more experience than me, not as a prelude to telling you all my thoughts on the subject.

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personally, i think there's enough reasonably smart money out there that there aren't that many lines that "eye-poppingly" wrong... and i don't actually know this, but i doubt the public's money is ever incredibly one-sided

seems like people on here find good lines on obscure stuff (winner of multiple WSOP, subway series), but those are exotics and in the first case, not sure the book honored the bets (someone can correct me)

[guids]

Very very few lines are "wrong" in the sense that you can spot an easy side and load up on it, if there were, Id be broke and all you guys would be vacationing in the bahamas.

[rjp]

Enough. [img]/images/graemlins/smile.gif[/img]

[beetman]

[ QUOTE ]
My question, which I'm not sure is quantitatively answerable, but that I do think is interesting, is: What percentage of lines are accurate enough that the juice makes both sides -ev, and what percentage of lines are profitably bettable (if you can identify the correct side to take)?

[/ QUOTE ]

Your question doesn't account for the fact that with line shopping, you can effectively eliminate a lot of the juice, if not all of it. For example, the Rutgers/USF game. I barely know anything about college football, but this morning the market line on the game was -3.5, so -3.5 -105 was pretty easy to find at the reduced juice books. I saw one "square" book offering USF +4 +100. By definition, at least one of those bets must be +EV, if not both of them.

Plus, if you include opening lines, even the sharpest books will sometimes put out soft opening lines which are quickly hammered into place. Pinnacle opened Ohio St -3 and Auburn -6 this week. Those bets are absurdly +EV, but they both lasted all of a couple minutes and you had to be ready to pounce on the opener (and the limits weren't all that high either.)

[20Five]

[quote By definition, at least one of those bets must be +EV, if not both of them.


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I dont see how bet could be +EV on both sides? I would imagine if a bet was +EV on one side, that would necessarily make the other side -EV, or am I missing something? [img]/images/graemlins/blush.gif[/img]

[playersare]

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I dont see how bet could be +EV on both sides? I would imagine if a bet was +EV on one side, that would necessarily make the other side -EV, or am I missing something?

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sportsbook's profit on their own lines comes from the built-in juice on the same game. if you can book two different sources where the resulting combined price creates a positive surplus of juice on your end, then you've made an +EV investment.