General Betting
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I would expect 95% of people on here to understand the value concept with Betfair being a place for sharp minds and all that, but for what it's worth (probably not much), here's my proof of it:
Value Concept:
Where
d = decimal odds
pr = Decimal probability of bet winning
d represents value if 1/d > pr
Proof Of Value Concept:
n = number of bets made
x = amount staked on each bet
p = total payout
d = decimal odds
pr = decimal probability of bet winning
Then,
nx = Total amount wagered
and
P = pr*d*nx
Let x = arbitrary value where x >0,
Where 1/d > pr,
as n tends to infinty, (p - nx) tends to infinity.
Where 1/d < pr,
as n tends to infinty, (p - nx) tends to minus infinity.
Value Concept:
Where
d = decimal odds
pr = Decimal probability of bet winning
d represents value if 1/d > pr
Proof Of Value Concept:
n = number of bets made
x = amount staked on each bet
p = total payout
d = decimal odds
pr = decimal probability of bet winning
Then,
nx = Total amount wagered
and
P = pr*d*nx
Let x = arbitrary value where x >0,
Where 1/d > pr,
as n tends to infinty, (p - nx) tends to infinity.
Where 1/d < pr,
as n tends to infinty, (p - nx) tends to minus infinity.
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Replies: 32
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Rowan86
I would expect 95% of people on here to understand the value concept If that were the case, Betfair would not exist. |
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Maybe they're just bad at quantifying value?
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How can 95% profit meaningfully from 5% ?
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Well, just because they understand that concept, doesn't mean they're going to agree on the prices.
Is your point that if 95% at least understood the concept, that wouldn't allow enough value to be exploited? |
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I think many more people understand the concept than profit from it.
You have to be exceptionally daft not to get it, but you can be not daft at all and still lose money. |
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I agree Lori.
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spot on lori
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I understand and agree Rowan, however i have found that probability is reliably inconsistent ! and therefore calculating pr becomes mind bogglingly difficult. particularly in correct scores where i have chosen to serve the term of my natural life.
Good luck all though. |
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Thanks for your post fatal statistics.
 I agree that the problem is obviously in trying to quantify pr. Interesting getting your perspective. |
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How's it going btw Scotbet? Thanks for posting on this thread. Nice to see you.
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First thing I look for in these calculations is the probability of winning value. It's used in Kelly.
Is pr calculated? NO Is pr used in a calculation? YES In that case, where does the value pr come from? OUT OF THE THEORIST'S HEAD So the whole thing is not worth the paper it is written on. |
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You have got the inequalities wrong. Also, where does pr come from ;-)
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Whoa, the posts go from newer to older..
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if urealy think this utter garbage is going to work ur a bigger mug than u sound....pathetic
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Damn. I did get the inequalities wrong. FFS.
CORRECTION: Value Concept: Where d = decimal odds pr = Decimal probability of bet winning d represents value if pr > 1/d Proof Of Value Concept: n = number of bets made x = amount staked on each bet p = total payout d = decimal odds pr = decimal probability of bet winning Then, nx = Total amount wagered and P = pr*d*nx Let x = arbitrary value where x >0, Where pr > 1/d, as n tends to infinty, (p - nx) tends to infinity. Where pr < 1/d, as n tends to infinty, (p - nx) tends to minus infinity. |
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Can't believe I did. Absolute SEETHING
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Can't believe I did that. Absolutely SEETHING.
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lol. Was waiting for a few people to ask 'how do we calculate pr?'
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swift-tuttle Joined: 22 Mar 04
Replies: 902 30 Aug 10 06:49 First thing I look for in these calculations is the probability of winning value. It's used in Kelly. Is pr calculated? NO Is pr used in a calculation? YES In that case, where does the value pr come from? OUT OF THE THEORIST'S HEAD So the whole thing is not worth the paper it is written on. Surely can't be any less meaningful than that pointless 'backing horses to win' thread you started.  |
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Sorry, I seem to have struck a nerve there
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lol. Sorry. You are right, but that wasn't the point of the thread. I just thought I'd write a proof for a bit of fun. There are one or two people who don't understand or haven't thought about the value concept though.
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I've thought about little else for the last few years now. All the recommendations tell you to go for Kelly but when I try to do that, I find it very difficult to put a value on the probability of the horse winning.
You're right to try and pin it down because I'm a firm believer in value being the key thing for successful punting. |
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Yeah, it's a hard working out the pr of the horse winning, but that's the name of the game.
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Don't the market makers work out the pr ( or try to) first inorder to set their opening prices ?
How else do you create a book ? Sorry if a stupid question. |
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Yeah, you're right Fine As Frog Hair. They try and work out the pr. Deffo.
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I think it's the bookies that work that out more than the market makers. If you can do this with a high degree of accuracy, you have a licence to print money.
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Dont forget the bookies can see the order flow...
If loads of people start placing bets on one horse, they can adjust there price. - As well as adjust the prices of all the horses in the race. (thik of the over/under run_). |
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Oh, when you said 'market makers', I thought you meant the bookies.
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I think there is some overlap, but market makers don't necessarily set the opening prices. The largest one certainly doesn't.
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Rowan86 Joined: 13 Jan 05
Replies: 1151 29 Aug 10 13:48 I would expect 95% of people on here to understand the value concept with Betfair being a place for sharp minds and all that, but for what it's worth (probably not much), here's my proof of it: Value Concept: Where d = decimal odds pr = Decimal probability of bet winning d represents value if 1/d > pr Proof Of Value Concept: n = number of bets made x = amount staked on each bet p = total payout d = decimal odds pr = decimal probability of bet winning Then, nx = Total amount wagered and P = pr*d*nx Let x = arbitrary value where x >0, Where 1/d > pr, as n tends to infinty, (p - nx) tends to infinity. Where 1/d < pr, as n tends to infinty, (p - nx) tends to minus infinity. ^ you forgot to add the random anomaly, when value backing in the 4.15 at windsor and getting chinned by a short head, seething with rage and lumping your whole bank on the next at wolves |
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LOOOOOOOOOOL Mythical.
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The inequalities were the wrong way round in that one you quoted though!
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