How badly is this bookie screwing up?

[DVO]

And what should the true odds be?

Here is a cut and paste from an EM I sent a friend. It involves a friend who is using a local bookie. Said bookie usually uses Vegas' lines. I hope this is understandable. I'm just wondering if I'm viewing this correctly, and how much the bookie is getting the wrong end of it giving 10/1.

I think I'll post in probability section also.
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Vegas offers 10/1 odds on correctly picking a 4 - bet parlay. Meaning, if you take the Vikes, Saints, Texans, and 49ers, say, and they each cover, you get a 10/1 return on your dough. ( By the way, aren't the true odds ~16-1? i.e. (.5) (.5) (.5) (.5) = .0625 = 16/1? )

This bookie, however, is offering the same 10/1 odds on 4 bet parlays that include halftime bets. In other words, you can take the Vikes to win the first and second halves of their game, and ditto the Saints, and those are your 4 bets. But of course they are related events ( The Vikes are a lot more likely to cover if they are ahead 22-0 at the half. Etc Etc.)

So instead of 4 unrelated events, the bookie is giving those odds on related events.

The beauty of it is, my friend isn't even bothering picking games any more. He's just using the law of large numbers....so if Vegas says the Colts are -6 in the first half and -12 for the game, he's just gonna flip a coin and take them to win or lose both halves. Then he'll do the same with some other team, and bang, there's his 4- bet parlay.

[playersare]

the outcome of the first half has virtually no bearing at all on the outcome of the second half, if they are treated as two separate betting entities (the way any normal sportsbook would do). to take your example, the vikings are up 22-0 at halftime. let's say in the second half, their opponent scores two touchdowns and minnesota only one. the opponent wins the second half (14-7) but the vikings still win the game 29-14. how does the 22-0 halftime score increase the likeliness that they will also score more points than their opponent in JUST the 2nd half? it doesn't.

straight odds parlays are almost always based on point spreads, not straight winners (1st half, 2nd half, game total, whatever). by allowing parlays on 2nd half spreads, the bookmaker retains his regular edge (since the 2nd half score is an independent event regardless of the 1st half or final score), and the bettor is at an additional disadvange if he has to parlay the 2nd half line blind (since the 2nd half spread isn't even calculated until halftime of that same game).

a halftime bet is NOT a bet on whether a team will win or cover the spread for the whole game WHEN THE GAME IS ALREADY HALF OVER. maybe that's what you misunderstood?

[DVO]

Playerscare

I should have been more clear.
The parlay is 1) first half 2) game, not 1) first half 2) second half.

IOW, I take Vikes -8 for the first half, and Vikes - 16 for the final score.

Ditto another game. Thus, 4 bets. It seems to me if the Vikes are leading the first half by 12, they have better than a 50% chance of winning the game by 16 or more.

My friend ran the numbers and says under this scenario, whoever wins or loses the first half, duplicates the result for the entire game 70% of the time.

So, in the exapmle above, if you take the Vikes on both bets, if the cover in the first half, they are 70% likely to cover the full game spread.

Thus I would guess the odds to be:

(.5) (.7) (.5) (.7) = .122% 0r 8.2 to 1.

Or I might be entirely wrong....thoughts?

[B00T]

Many sites do not allow correlated parlays. You cannot bet a heavy favorite and the Over in the same college football game say: OSU -42 vs whoever and O 62. He is letting you do exactly that in your example.

I think you are entirely right.

[KJL]

IS this just for 4 team parlays or would the same rules apply for 2 teamers?

[MyTurn2Raise]

2-teamer would be pretty obvious

this is a golden goose, I wouldn't want to ruin it right away

[Thremp]

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this is a golden goose, I would rape it, eat it, and take its babies before anyone else had a chance

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[iggymcfly]

Your friend should bet favorites and overs or unders and dogs to make it less obvious to the bookie. If he starts winning parlaying 1st halfs and game lines, it's going to be pretty friggin obvious to the bookie what's going on.

Betting -28 and over 52 though? That might have a little longer shelf life.

[kyleb]

[ QUOTE ]
[ QUOTE ]
this is a golden goose, I would rape it, eat it, and take its babies before anyone else had a chance

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Exactly.

[NajdorfDefense]

[ QUOTE ]
[ QUOTE ]
this is a golden goose, I would rape it, eat it, and take its babies before anyone else had a chance

[/ QUOTE ]

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You should study the concept of 'long-term greedy.'

Of course, if you think other of his bettors will figure this out insta-like, than yes.