# Help me understand/disprove a flawed logic

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 Author Topic: Help me understand/disprove a flawed logic  (Read 1343 times)
Alfa1234
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« on: February 12, 2016, 10:07:13 PM »

So guys I was thinking.  The premise of every bookie out there is, they want a balanced book and have an average juice of 4 to 12% right?

Basically, without value betting, any punter will eventually lose money as the bookie has a mathematical edge.  Unless you start analysing games etc etc it is a given you'll lose money eventually.

So, if you "randomly" bet on games without taking the odds into consideration, eventually you'll bust your account if you just keep betting long enough.  You could have a pretty long lucky streak...but eventually you'd bust.  Correct?  I believe there is no mathematical or logical way that could "not" happen.

What if you were to lay every random bet you take at the soft bookie at an exchange, no matter what lay odds, arb or no arb, and just add 10% to your stake every time + add the juice of the bookie to your lay stake? Would this, long term, not make money or is my math on this flawed somewhere.  Let's say you win 20bets in a row at the soft, you'd have to add the juice of the bookie (basically the negative arb bet) to your exchange bet at every bet + add a % profit on top.  Granted, you'd need a pretty big bank in case of a very long "unlucky streak".

You lose money at the bookie, which is a given.  So that makes you win money at the exchange in the end...right?  Am I completely going crazy here?  Where is the flaw in my logic, which I know has to be there as it does not make sense...

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middler
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« Reply #1 on: February 12, 2016, 10:18:46 PM »

I'm not completely sure if I get your point.
The only thing that is clear here is that if you don't find value either backing or laying the bets, you will end up losing (statistically) on both sides.
It doesn't matter how much money you place at each side. And it certainly doesn't matter if you cover the juice on one side by increasing your stake. This won't make the laying odds lower (better for you).
What you are trying to do here is get an advantage play, and that is all about probabilities. If the accumulated probability of the outcomes does not get you an arb, you are losing value on every bet.
Therefore, it is the same as betting on odds 1,99 and 1,99 every time. No matter if you place 99 and 101, or 100 and 100, on the long run, you will en up losing money unless there is an overvalued side.
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Alfa1234
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« Reply #2 on: February 12, 2016, 10:33:31 PM »

My (flawed) point is.  If it's a mathemacial certainty you'll lose money at a softbookie because of their juice, how is it not a mathematical certainty you'll win money at an exchange by betting the exact opposite + juice + profit % at that exchange?
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raizzak
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« Reply #3 on: February 12, 2016, 10:40:57 PM »

the flaw is when you lose at the exchange if i understand correctly you say that you place something at let's say 50 -50 (1.90,1.90) at soft with something equilevelant at sharp/ exchange but you also bet something to get the juice back. In that case (if understand you correctly) the lose situation will come when you will lose at sharps
 « Last Edit: February 12, 2016, 10:42:43 PM by raizzak » Logged

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raizzak
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« Reply #4 on: February 12, 2016, 10:52:04 PM »

100 x1.90 = 190 at soft and you have the opposite at 2 on a sharp ( it is the same pretty much if you are laying)
if you had an arb you would 190/x <100 and you get the profit if you do it now it is >100 so you lose

so if i understand you, you will place something more @ 2 let's say 110 * 2 = 220 so you have 2 bets one of 100 and one of 110. 50% of the time you will get 190 back and 50% of the time 220 while every time you risked 210 if you maintain a perfect 50% hit rate on either side you will have 500*190 =95000 and 500 * 220=110000 while you risked 1000*210 = 210000

95000+110000= 205000 so you lost money
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cristi13
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« Reply #5 on: February 12, 2016, 11:15:58 PM »

assuming a situation with 50-50 chances, odds at bookmaker 1.95, best lay odds at exchange 2.05 equals 1.95 odds.
So you bet \$100 on X at the bookmaker and \$110 on Y at exchange.
When X wins, you have \$100x1.95=\$195 minus \$210 investment = -\$15
When Y wins, you have \$110x1.95=\$214.5 minus \$210 = +\$4.5
They each win 50% so your average return is (-15+4.5)/2 = -\$5.25
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Alfa1234
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« Reply #6 on: February 13, 2016, 09:55:13 AM »

assuming a situation with 50-50 chances, odds at bookmaker 1.95, best lay odds at exchange 2.05 equals 1.95 odds.
So you bet \$100 on X at the bookmaker and \$110 on Y at exchange.
When X wins, you have \$100x1.95=\$195 minus \$210 investment = -\$15
When Y wins, you have \$110x1.95=\$214.5 minus \$210 = +\$4.5
They each win 50% so your average return is (-15+4.5)/2 = -\$5.25

What if your 2nd bet at the exchange adds the first negative return into it?  So you'd bet 223 at the exchange (adding the juice) the 2nd time and so on.  It's a kind of martingale I suppose, but based on the premise you'll eventually lose at the bookie hence win at the exchange.
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Thordin
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« Reply #7 on: February 13, 2016, 10:16:37 AM »

It's a kind of martingale I suppose, but based on the premise you'll eventually lose at the bookie hence win at the exchange.

It is a martingale, and the longer you do it the more you lose.
Cristi gave a good explanation, if you want to adjust the stakes do it on his formula and you will see that the -5.25 will just decrease even further.
And that is your probabilistic return, well in this case loss, and thats how you should calculate.
Everytime you make a bet, you lose that amount, your base line.
Actual return will differ. Luck / variance will fluctuate this result, give it ups and downs but regression to the means will be dragging it towards it and the more you bet, the closer the number will be to your probabilistic return.
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dealer wins
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« Reply #8 on: February 13, 2016, 11:08:16 AM »

You will win money at the soft book in the long run (assuming you are arbing and hence taking their out of line odds).

If you are randomly placing bets at a soft book and laying, then you will lose in the long term at both the soft book and also at the exchange due to commission and over-round there.
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Alfa1234
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« Reply #9 on: February 13, 2016, 11:54:00 AM »

It's a kind of martingale I suppose, but based on the premise you'll eventually lose at the bookie hence win at the exchange.

It is a martingale, and the longer you do it the more you lose.
Cristi gave a good explanation, if you want to adjust the stakes do it on his formula and you will see that the -5.25 will just decrease even further.
And that is your probabilistic return, well in this case loss, and thats how you should calculate.
Everytime you make a bet, you lose that amount, your base line.
Actual return will differ. Luck / variance will fluctuate this result, give it ups and downs but regression to the means will be dragging it towards it and the more you bet, the closer the number will be to your probabilistic return.

Perfect, thanks.
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Sampong
Newbie

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« Reply #10 on: February 13, 2016, 08:18:23 PM »

So guys I was thinking.  The premise of every bookie out there is, they want a balanced book and have an average juice of 4 to 12% right?

Correct

Basically, without value betting, any punter will eventually lose money as the bookie has a mathematical edge.  Unless you start analysing games etc etc it is a given you'll lose money eventually.

Correct

So, if you "randomly" bet on games without taking the odds into consideration, eventually you'll bust your account if you just keep betting long enough.  You could have a pretty long lucky streak...but eventually you'd bust.  Correct?  I believe there is no mathematical or logical way that could "not" happen.

Again - correct

What if you were to lay every random bet you take at the soft bookie at an exchange, no matter what lay odds, arb or no arb,

Then you would effectively double the statistical disadvantage. You are paying the edge at the bookmaker, and you are also paying the commission at the exchange - as dealer wins has pointed out.

and just add 10% to your stake every time + add the juice of the bookie to your lay stake? Would this, long term, not make money or is my math on this flawed somewhere.

Your maths is flawed. You can't beat probabilities with staking systems. You will be able to find plenty of articles debunking martingale betting on the internet to inform you.

You lose money at the bookie, which is a given.

Correct, unless you are taking arbs, which are effectively value bets at soft books but that's a whole different discussion.

So that makes you win money at the exchange in the end...right?

No, you will lose a margin at both. See above.

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