General discussion : Comparing bookmakers for odds

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Lucacrebbe
Posts: 171
Joined: Thu Sep 21, 2017 3:23 pm

Sat Jul 07, 2018 3:09 pm

For a lot of time I have struggled myself searching for the best tool for making predictive statistical analisis to try to reach the accurates odds a match should have, and then try to estrapolate the value from the odds that other players were offering.

Then I came to the conclusion that no one is better than the Bookmaker's statistical analisy... but so many times I have seen a lot of bookmakers which offered a tennis player or a football team at a ridiculous overpriced odd... so I was thinking ''Why are they overpricing this player so much?''... ''How wrong are their satistical tools?''

Anyway it's a bad argument... because thanks to statistical models, they will win in the long run, no matter if a player seems overpriced to me in a particular moment. If the software has calculated that odd, it's because matematically that's the odd of winnning for this player (minus the house edge)

So i was thinking to trust much more the bookmaker's pre-match odds and trusting less the bookmaker's in-play odds because the in-play odds are gathered only thanks to the volume of bets made by bettors... so if the bookmaker will see that the volume of bets is much more on a team rather than the other one, they will reduce and increase the odds properly (to ensure themselves a sure profit, no matter how the game will end up)
Whilst the pre-match odds are gathered thanks to a good statistical/matematical analisy because the first bettors who bet pre-match are more important for a bookmaker, because at first glance they don't have a real volume.. so they have to be the more accurate as possible to guess the odds of a match.... so the first pre-match odds can be seen as a fundamental point of resistence/support in case then in-play the odds would move from this value

My idea is that --during the match- the odds will often came back to the the odd's pre-match value made by bookmakers, because they are made upon sofisticate quantitaive analisy tool

Am I right, what's your opinion?

Derek27
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Location: UK

Sat Jul 07, 2018 5:15 pm

If you think bookies are always right the best advice is to give up betting. Bookies are often wrong and the proof of it is in the diverse odds you sometimes get for the same event.

Software can accurately calculate probabilities in fixed-probability games but not on sporting events.

The reason tennis odds in-play often come back to pre-match odds is because it is mathematically impossible not to unless the favourite dominates the the betting goes one way - have you not noticed by now that the odds fluctuate?

The pre-match odds have little relevance once the match has started - what's happening on court is for important. I'm currently working on a VBA program to simulate 1000's of games and calculate what the probabilities of winning would be if the player's won random points based on a chosen winning serve percentage for each player, but it's more of an exercise, I don't know how useful it will be.
Last edited by Derek27 on Sat Jul 07, 2018 6:21 pm, edited 1 time in total.

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Dallas
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Joined: Sun Aug 09, 2015 10:57 pm

Sat Jul 07, 2018 5:43 pm

Bookmakers build profits into their prices, depending on the sport this can be up to 30% or sometimes even higher so I wouldn't advise trying to use their prices as a basis of the chances of someone/thing winning.

Lucacrebbe
Posts: 171
Joined: Thu Sep 21, 2017 3:23 pm

Wed Jul 11, 2018 6:13 am

Derek27 wrote:
Sat Jul 07, 2018 5:15 pm
If you think bookies are always right the best advice is to give up betting. Bookies are often wrong and the proof of it is in the diverse odds you sometimes get for the same event.

Software can accurately calculate probabilities in fixed-probability games but not on sporting events.

The reason tennis odds in-play often come back to pre-match odds is because it is mathematically impossible not to unless the favourite dominates the the betting goes one way - have you not noticed by now that the odds fluctuate?

The pre-match odds have little relevance once the match has started - what's happening on court is for important. I'm currently working on a VBA program to simulate 1000's of games and calculate what the probabilities of winning would be if the player's won random points based on a chosen winning serve percentage for each player, but it's more of an exercise, I don't know how useful it will be.

I have red the blog of a tennis trader. He said:

''I always use to see the bookmaker's odds, because they are the most accurate, they spent a lot of time with their statistical department on odds''


I would say that the pre-match odds, are realistically and statistically the most accurate odds Dereck... I please understand my tought:

The bookmaker have the most sofisticated software to calculate odds, they don't have an exange (back or lay) so the first odds they give must be the most accurate as possibile

Imagine a match Juventus VS Livorno

What about if they would give to juventus an odd of 1.05 and X2 for Livorno would be priced at an odd of 40?

Well if a lot of bettors back X2 livorno for 40 and imagine if Livorno would really end up with a drawn (X) then the bookmaker would take a big hit.....

During the live match is a different thing instead, because the bookmaker are used to balance the odds checking the volume of the bets... so if there would be a lot of volume of bets for X2 Livorno at the price of 40, then the Bookmakers will decrease the odd to an odd that generates a profit for them anyway, not matter how the match will end up... ok?

I am saying that during the match the odds are NOT based on statistical parameters, but on the volume of bets.

So, if you would like to have the most accurate statistical odds , you should have to check odds set by bookmakers PRE.match

I am not saying those are the real odds, but those are the most (statistical) accurate

Since they are the most accurate from a statistical point of wiev, they can be seen as an important point of support / resistence... as a mean ..... as average mean.... for example if the odds goes too far from this mean you'll know that it's time to back / lay

Example: X2 livorno drops from 40 pre-match to 10 in play... well it's time to lay because it's gone too much far from the standard deviation set up by bookmaker odd (40) and most likley it will come back to the mean

Derek27
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Wed Jul 11, 2018 6:43 am

Lucacrebbe wrote:
Wed Jul 11, 2018 6:13 am
The bookmaker have the most sofisticated software to calculate odds, they don't have an exange (back or lay) so the first odds they give must be the most accurate as possibile
Bookies often contract statisticians to develop software and compile the probabilities/odds for football.

My brother's a statistician who's often done such work, so bookies don't have the most sophisticated software - my brother has, together with the mathematical know-how. There are clever people on both sides of the betting counter!

Bookies also have the disadvantage of having to price up every match, whereas bettors can be more selective. The proof of the pudding is in the number of arbing opportunities, which by definition means that the bookies are making mistakes. My brother places quite sophisticated bets, backing teams to be promoted or relegated and counter spread bets, not quite arbing but getting positions where he gets long odds on eventualities that should be odds-on.
Lucacrebbe wrote:
Wed Jul 11, 2018 6:13 am
During the live match is a different thing instead, because the bookmaker are used to balance the odds checking the volume of the bets... so if there would be a lot of volume of bets for X2 Livorno at the price of 40, then the Bookmakers will decrease the odd to an odd that generates a profit for them anyway, not matter how the match will end up... ok?

I am saying that during the match the odds are NOT based on statistical parameters, but on the volume of bets.

...

Example: X2 livorno drops from 40 pre-match to 10 in play... well it's time to lay because it's gone too much far from the standard deviation set up by bookmaker odd (40) and most likley it will come back to the mean
During a match the odds are not just determined by the volume of bets but what's going on on the pitch.

If "Livorno" drop from 40 pre-match to 10 in-play, whether or not it's time to lay depends, amongst other things, on the score. What if they're two goals up at half-time?

At half time the pre-match odds are of little more than interest. Outsiders sometimes win, in which case they reach 1.01, so you have to reassess the situation.

Lucacrebbe
Posts: 171
Joined: Thu Sep 21, 2017 3:23 pm

Wed Jul 11, 2018 8:01 am

Derek27 wrote:
Wed Jul 11, 2018 6:43 am
My brother places quite sophisticated bets, backing teams to be promoted or relegated and counter spread bets, not quite arbing but getting positions where he gets long odds on eventualities that should be odds-on.

Could you please explain in a simpler way this? I have not understood it

Derek27
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Location: UK

Wed Jul 11, 2018 8:19 am

It's similar to arbing, only one bet is with a regular bookie, the other is a spread bet. For example, he might back a team to get relegated and then place a spread bet on the number of goals they score in the season, when he's calculated the probability of both bets losing is very small for his potential reward.

He basically scans the betting markets for all sports and finds the flawed odds, then works out a way to secure a profit.

stueytrader
Posts: 288
Joined: Tue Dec 15, 2015 6:47 pm

Wed Jul 11, 2018 11:01 am

Derek27 wrote:
Wed Jul 11, 2018 8:19 am
It's similar to arbing, only one bet is with a regular bookie, the other is a spread bet. For example, he might back a team to get relegated and then place a spread bet on the number of goals they score in the season, when he's calculated the probability of both bets losing is very small for his potential reward.

He basically scans the betting markets for all sports and finds the flawed odds, then works out a way to secure a profit.
Sounds similar to the approach I will deliberately take to trading some selections - essentially leave yourself with a bet, but one at much better odds than there would have been by simply placing a 'bet'.

Derek27
Posts: 2204
Joined: Wed Aug 30, 2017 11:44 am
Location: UK

Wed Jul 11, 2018 4:52 pm

stueytrader wrote:
Wed Jul 11, 2018 11:01 am
Derek27 wrote:
Wed Jul 11, 2018 8:19 am
It's similar to arbing, only one bet is with a regular bookie, the other is a spread bet. For example, he might back a team to get relegated and then place a spread bet on the number of goals they score in the season, when he's calculated the probability of both bets losing is very small for his potential reward.

He basically scans the betting markets for all sports and finds the flawed odds, then works out a way to secure a profit.
Sounds similar to the approach I will deliberately take to trading some selections - essentially leave yourself with a bet, but one at much better odds than there would have been by simply placing a 'bet'.
When spread betting you have no choice because your potential return is variable. I guess it's a case of comparing worst case / likely /best case scenarios.

Lucacrebbe
Posts: 171
Joined: Thu Sep 21, 2017 3:23 pm

Thu Jul 12, 2018 4:03 am

Derek27 wrote:
Wed Jul 11, 2018 8:19 am
It's similar to arbing, only one bet is with a regular bookie, the other is a spread bet. For example, he might back a team to get relegated and then place a spread bet on the number of goals they score in the season, when he's calculated the probability of both bets losing is very small for his potential reward.

He basically scans the betting markets for all sports and finds the flawed odds, then works out a way to secure a profit.
Where can I do spread betting? How is the revenue? I immagine it works just like the futures.. you choose up or down... in this case ''relegate to Serie B'' or ''it remains into Serie A''

Then he hedges his spread bet with another bet, on the number of the goal.

Which tecnique does he use to see that the odds are flawed and they have an advantage for your brother?

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