Title: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:57:16 PM
I have been meaning to put all the maths and betting stuff in one thread for some time.
It will be a place to discuss optimal mathematical strategy for all the below and try and explain it with some maths. I'll call it optimal mathematical strategy, but think it could be easily described as optimal strategy for most of us. I will also try and give rough rules about when these bets become no brainers and others where they should be avoided. If people ask what they should do with a free bet, we can just direct them here, and hopefully the answer will be easier to find than if it was buried on page 1145 on TfT. At the start I am going to cover: free bets; bets with money back/free bets for second; bets with money back/free bets for second to the favourite; the Richard Hughes promotion for Ascot; dirty each way best price guarantees If a bookie offers something that doesn't look like any of the above, we can discuss it here. Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:57:27 PM
Free BetsThe usual format of a free bet is that you get the correct price on your free bet, but lose the assumed stake money. I used to fall into the trap of using free bets to back short price outcomes thus locking up some free bet money. Though I have made hundreds of pounds over the years, I have definitely wasted hundreds more in EV over the years. So next time somebody says "If I back Barcelona to win and then back them straight away after the match starts then I effectively get Barcelona at evens instead of 1/2, then please point them here. There are two basic rules of free bets. 1) Only use them to back horses/events at big prices.2) Never use them to back each way. Say you had a £50 free bet. 1) In this thread I will estimate a chance of winning, the reality will tend to be that I am overstating the chance of winning as Bookies make a profit. But the estimates are going to be close enough to correct to show why we should always choose a big priced horse/event. If you back a 1/2 chance, you can assume that it has a 67% chance of winning. When we win, we win £25. Hence your expected return is £25 x 0.67 = £16.67 If you back an evens chance. Assume it has a 50% chance of winning. When we win, we win £50, your expected return is 0.5 x £50 = £25 If you back a 2/1 chance. Assume it has a 33% chance of winning, your expected return is 0.333 x £100 = £33.33 If you back a 3/1 chance. Assume it has a 25% chance of winning, your expected return is 0.25 x £150 = £37.50 and so on. If we carry on, then the expected return from backing: a 5/1 chance is £41.67, a 7/1 chance is £43.75, a 10/1 chance is £45.45, a 14/1 chance is £46.67, a 20/1 chance is £47.62. I think once you get past 7s or so, it is probably is a bit flatter than illustrated, as bookies tend to offer genuine 40/1 and 50/1 chances at 33/1. So I think the answer is make sure you at least get a decent price on your free bet. I am sure that if you take a horse from 7s upwards, you aren't losing a lot of EV by using the free bet this way. There are exceptions. Sometimes the free bets are time limited and it is always better to take any bet on than let it expire, hence sometimes I take shorter prices than I would normally like, and on other occasions you may think a 5/1 horse should be 3s, so there isn't a lot of harm done there. 2) why you should never use free bets to back each way. Assume I back a 4/1 horse each way getting quarter the odds, if it gets a place my return on a normal bet would be my stake back on a normal bet. Under a free bet I lose my initial stake so my actual return is zero (£50 on a normal bet). Likewise, if I took 6/1, I'd only get £25 back (£75 on a normal bet), and if I took 10s, I'd only get £75 back (£125 on a normal bet). Basically you are killing a lot of EV even backing big priced runners each way. Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:57:38 PM
Money Back Offers if Your Horse is Second.There seems to be a lot of these offers around at the moment and taking up the offer is usually correct, but there are definite exceptions. I haven't yet had an account closed that has obviously been as a result of taking up offers, though have had my access to offers removed from an account where I made most of my money without using offers. I think the golden rule of taking these offers is: Short is GoodIf you have two horses in a race that are 2/1 and 5/1. Without any extra research I can assume the 2/1 horse is more likely to be first, but not only that I can see that the 2/1 horse is more likely to be 2nd. Getting the horses that are more likely to be 2nd is where you get the value from. So if I have 5 minutes, I can check that the 2/1 price is close to the Betfair price and close to the best price. If that checks out then I can assume I am not going to lose much value from the bet. Not only that but because the Betfair market is close to perfect I can assume that backing the 2/1 is going to be the best option way more of the time than the 5/1 chance and conclude I don't add much by doing "research". It is always the case that shorter is always better, in the Coronation Cup the other week, I was fairly certain that Dunaden was more likely to be 2nd than first, but that was only because the favourite was so short (2/5). Maths Throughout the examples, I will assume that Betfair midprice is a good proxy for the real chance of the horse winning a race. Assuming that we have a money back offer and are betting on a horse that is 2/1 with a bookie under this offer and mid price 3.25 on Betfair. Assuming we get cash back if 2nd. Our expected return without the cash return from a £50 bet is 50/3.25 x 3 = £46.15. If the horse is a 30% chance of finishing first, we can assume the horse is probably around a 25% chance to be 2nd. So our return from the money back offer is an additional .25 x 50 = £12.50 So total expected return is £46.15 + £12.50 = £58.65 or an ROI of 17%. If your return is a free bet, if you use it wisely, you probably lose 10% in the long run from the £12.50, so your ROI drops to 15% The maths becomes less compelling as the price of our original horse gets bigger and if we move away from the Betfair price. Assume that we have a money back offer and are betting on a horse that is 8/1 with a bookie under this offer and mid price 10s on Betfair. Assuming we get cash back if 2nd. Our expected return without the cash return from a £50 bet is 50/10 x 9 = £45. If the horse is an 11% chance of finishing first, we can assume the horse is probably around an 11% chance to be 2nd. So our return from the money back offer is an additional .11 x 50 = £5.50 So total expected return is £45 + £5.50 = £50.50 or an ROI of 1%. If your return is a free bet, if you use it wisely, you probably lose 10% in the long run from the £12.50, so your ROI drops to 0% Interestingly you get a better ROI backing a 2/1 chance that is a genuine 9/4 chance than you do backing a horse that is 8/1 and should be 8/1. If you don't know much about the horses, then just assume short is best. Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:57:47 PM
Money Back Offers if Your Horse is Second to a Named Horse.These offers aren't nearly as generous as the offers that give a return if your horse is 2nd to any horse. I'd say it is easy to lose money using these offers if you aren't careful I think the golden rule of taking these offers is: Short prices on both horses are essential If you back a horse at 6/1 and the offer is a return of cash if your horse is 2nd to another 6/1 chance, then the chance of them finishing one to two in the correct order is going to be something close to 2%. If the bookie then offers you worse odds than Betfair that aren't even best odds then it is an easy offer to turn down this offer. I was sent an offer very close to this early on Saturday (I actually had to pick 2nd to an unnamed favourite, so it was even worse). To take up an offer like this it is very important that both horses are short. Maths Throughout the examples, I will assume that Betfair midprice is a good proxy for the real chance of the horse winning a race. Assume we are offered money back if our 5/1 horse is 2nd to an evens favourite Assuming that we have a money back offer and are betting on a horse that is 5/1 with a bookie under this offer and mid price 6.5 on Betfair. Assuming we get cash back if 2nd. Our expected return without the cash return from a £50 bet is 50/6.5 x 6= £46.15. If the horse is a 50% chance of the evens horse finishing first, and we can assume the horse is probably around a 30% chance to be 2nd if the evens horse wins. So our return from the money back offer is an additional .5 x.3 x 50 = £7.50. So our return is £53.65 or an ROI of 7%. If your return is a free bet, if you use it wisely, you probably lose 10% in the long run from the £7.50, so your ROI drops to 6% The maths becomes less compelling as the price of each of the horses gets bigger and if we move away from the Betfair price. Your probably struggling to make a positive return once the horse we have to finish 2nd to gets much above 2/1 unless the Bookie is right on Betfair prices for the horse we back or we are picking our horse with an edge. If you see this offer in a big handicap, it should be pretty easy to just bin it without much investigation. Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:57:55 PM
Money back if a named horse winsThese bets have the same additional value whichever horse you back (barring the named horse). So if you are backing blind, you want to get the horse that is best value vs Betfair.You can approximate the chance of a horse winning by taking betfair mid price. So if it is available to back at 5.4 and lay at 5.5, the mid price is 5.45. If your bookie offers you 4/1 on this horse (which equates to 5 in decimal odds) you are getting back 5/5.45 = 91.7% of the value of the bet from taking the bad horse. So long as the refund you get from the named horse is worth more than 8.3%, then this bet is +EV. Example There is an example at Royal Ascot where Paddy Power are giving you money back if Animal Kingdom wins the Queen Anne. Given Animal Kingdom is odds on, you get just over £25 (or 51.6%) of value added to your free bet if they allow you to bet £50 (The offer is max £100, I can't get £50 on). This enables you to take much lower prices on Paddy Power than you would do elsewhere, and in addition they have best price guaranteed on the race, so you aren't going to get a bad price no matter what they are quoting now. On the prices they quote right now the best value hoses against Betfair are Penitent, Gregorian, Declaration of War, Gabriel, Chil The Kite, Aljamaheer, Trumpet Major, Sovereign Debt, Elusive Kate and Trade Storm, in that order. I think you can assume that those higher up the betting are going to start closer to best price than those at the bottom, so I probably wouldn't choose Penitent or Chil The Kite. Whatever you do you should definitely take the Paddy Power bet if you can as the added value is so good. There was a similar offer on the World snooker where you got money back if O'Sullivan won. The maths in that case were much closer as O'Sullivan was about 6/1. In that case, I could only find one or two players worth backing. This is because if the named horse is 6/1 the bookie prices have to be much closer to the true (or Betfair) odds in order to be +EV. Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:58:04 PM
Money back if a named jockey placesThe value of this offer is roughly 90% of the value of 1/(probability of placing of the named jockey) x bet size x probability of your choice losing. So the offer is 1) more valuable the shorter the price of the Jockey's rides, 2) more valuable the bigger the price of your choice of horse. Needless to say, you want to pick a horse that is near the Betfair midprice. Example 3.45 Ascot tomorrow Probability Toronado places is 1/1.7. The value of the free bet before adjustment for the probability our horse lose is 25/1.7 = £11.91 Assuming betfair mid price reflects true odds Mars is the best bet, value of Mars bet alone = 25 x 13(BetVictor's price)/14.75(Betfair Mid) + (1-1/14.75) x 11.91 = £33.03 The next best mathematical bets are Dawn Approach and Magician. Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:58:13 PM
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Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 15, 2013, 09:58:23 PM
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Title: Re: Mathematics and Betting ThreadPost by: The Camel on June 16, 2013, 01:14:25 PM
Brilliant thread, thanks for doing this Doobs.
Title: Re: Mathematics and Betting ThreadPost by: Marky147 on June 16, 2013, 01:18:00 PM
Brilliant thread, thanks for doing this Doobs. Definitely this! Looking forward to plenty of nosebleeds as I try to follow. Title: Re: Mathematics and Betting ThreadPost by: TightEnd on June 16, 2013, 01:29:56 PM
Brilliant thread, thanks for doing this Doobs. Exactly. Thanks very much, very useful Title: Re: Mathematics and Betting ThreadPost by: outragous76 on June 16, 2013, 01:36:18 PM
I assume we can ask questions?
Free bet Using your theory, is there a point of diminishing return? (Ill assume not, just ever decreasing increase?) Therefore, although your point is excellent, there must be a point where we say a return is better than bigger ev? Hence, and where my assumptions lead to, is there a sweetspot price we should aim for? Title: Re: Mathematics and Betting ThreadPost by: The Camel on June 16, 2013, 01:49:38 PM
I'd be interested on the mathematics of bad each way races.
How much ev on the win part of the bet can we afford to give up when the place part of the bet is clearly +ev? I do it by intuition only at the moment. Title: Re: Mathematics and Betting ThreadPost by: doubleup on June 16, 2013, 01:53:12 PM
I'd be interested on the mathematics of bad each way races. How much ev on the win part of the bet can we afford to give up when the place part of the bet is clearly +ev? I do it by intuition only at the moment. Here's a calculator https://docs.google.com/file/d/0Byg8Wbbo5p2ucDN2WVdueENUYzA/edit?usp=sharing you have to download it - you can't put the data in on google docs Title: Re: Mathematics and Betting ThreadPost by: The Camel on June 16, 2013, 01:55:02 PM
I'd be interested on the mathematics of bad each way races. How much ev on the win part of the bet can we afford to give up when the place part of the bet is clearly +ev? I do it by intuition only at the moment. Here's a calculator https://docs.google.com/file/d/0Byg8Wbbo5p2uN3dRYlQwaTlhNE0/edit?usp=sharing you have to download it - you can't put the data in on google docs Great stuff, thanks. Title: Re: Mathematics and Betting ThreadPost by: kukushkin88 on June 16, 2013, 02:00:03 PM
This forum is probably the most valuable betting resource on the internet. Genuine thanks to all concerned. Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 16, 2013, 03:24:19 PM
How much ev on the win part of the bet can we afford to give up when the place part of the bet is clearly +ev? I do it by intuition only at the moment. Here's a calculator https://docs.google.com/file/d/0Byg8Wbbo5p2uN3dRYlQwaTlhNE0/edit?usp=sharing you have to download it - you can't put the data in on google docs I was thinking about putting together a spreadsheet that did calcs like this. Saves me the trouble. Thanks Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 16, 2013, 03:41:33 PM
I assume we can ask questions? Free bet Using your theory, is there a point of diminishing return? (Ill assume not, just ever decreasing increase?) Therefore, although your point is excellent, there must be a point where we say a return is better than bigger ev? Hence, and where my assumptions lead to, is there a sweetspot price we should aim for? If you look at the calcs in the free bet post, once you get to 5/1 you have already captured over 80% of the maximum value of the free bet, once you get to 10/1 you have over 90% of the value. Given you aren't likely to find many genuine 50/1 chances priced at 50/1, there is probably a point where you aren't getting any extra value and just getting more variance from your bets. I'd say once you get past 10/1 you aren't going to be able to push much extra return out of your free bet. In other calcs I have assumed that you lose 10% of the value of the free bet. To do much better than this you probably have to spend some time analysing form etc. So if I was to guess at a sweetspot, I'd say about 10s to 12. Ofc if you find a good 16/1 chance I would just snap it up , regardless, and the same goes for an 8/1 chance you think should be 7s. Title: Re: Mathematics and Betting ThreadPost by: gouty on June 16, 2013, 05:08:17 PM
Nice read Doobs. You explain quite complex concepts concisely and I have learnt something today which is always a good thing.
Thank you. Title: Re: Mathematics and Betting ThreadPost by: tikay on June 16, 2013, 05:13:00 PM
Superb thread Doobsy, thank you. Maybe we could run a little fantasy "Free Bet" Thread, with a fictional bankroll, to see some examples in action. Title: Re: Mathematics and Betting ThreadPost by: outragous76 on June 16, 2013, 06:56:15 PM
cheers doobs
I dont bet much, but your explanations make things really clear. wpwp on the thread Title: Re: Mathematics and Betting ThreadPost by: Karabiner on June 16, 2013, 10:18:49 PM
Doobs, I had a situation yesterday where I fancied punting a horse in a good EW race with 18 runners and the best price was 10/1 1-2-3-4 but a couple of firms were paying 1-2-3-4-5 but only offering 8/1.
How on earth can you figure out which of those is better especially when 12.5 was available on betty win only which is what I actually went for? Of course it came 5th. :( Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 17, 2013, 09:31:39 AM
Doobs, I had a situation yesterday where I fancied punting a horse in a good EW race with 18 runners and the best price was 10/1 1-2-3-4 but a couple of firms were paying 1-2-3-4-5 but only offering 8/1. How on earth can you figure out which of those is better especially when 12.5 was available on betty win only which is what I actually went for? Of course it came 5th. :( Without seeing the shape of the race, or the Betfair place market, it would be difficult to estimate which is better out of 10/1 each way or just backing on the nose on Betfair. If it is a genuinely good each way race, I suspect it is best to go to the bookies, but it is hard to be definitive about it. I think it must be the case that 10/1 with first 4 must be better than 8/1 first 5. The place terms must be worth about the same, but you get better win odds with the 10/1 chance. I think the race would have to look something like exactly 5 horses under 10/1 and everything else very big prices for the 8/1 and 5 places to be better. So I think the choice should have been between betting on the nose, and betting quarter first 4, so you should always lose if you made the best choice. Title: Re: Mathematics and Betting ThreadPost by: Karabiner on June 17, 2013, 10:10:44 AM
Cheers Doobs, it's nice to know that my instincts were correct.
Title: Re: Mathematics and Betting ThreadPost by: doubleup on June 17, 2013, 11:30:15 AM
re the extra place. I would think that you aren't going to be that far out if you estimate that mid-longer prices will be placed 5th with the same odds as they would win. If you think about a genuine 2-1 shot - it will win 33% of time but obv be placed less than 100% of the time, so its placings will be skewed towards 1st place. As odds lengthen this skewness decreases and likelyhood of being in any position equalises. Imagine a 20 horse race with every horse of equal ability - they would have an equal chance of placing in every position, so the odds of winning would be exactly the same as placing 5th. When you move on to genuine outsiders these would begin to be skewed towards last place so the probability of 5th place would be greater than first. Title: Re: Mathematics and Betting ThreadPost by: simonnatur on June 17, 2013, 01:04:47 PM
"Nigeria's best current forward and likely starter up the front is Aide Brown Ideye. He is best priced 3/1 to be first player to score vs the hapless part time Pacific Islanders, and best priced 1/2 to score anytime. Bet365 are offering 3/1 and a third the odds each way to score anytime."
I tried to work out EV for backing him e/w as FGS, and started by assuming anytime GS was priced correctly with margin added. Therefore assumed true odds of him scoring anytime are 48% assuming £1 e/w, so (-2*0.52) etc represents 52% of time he fails to score and we lose our stake... =(-2*0.52)+(0*(0.48*(1-H2)))+(4*(0.48*H2)) cell H2 we input % that he is FGS when scoring IF (big if) I've done this correctly we break even only if he scores first in 55% or more of the matches in which he is a goal scorer Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 17, 2013, 02:57:33 PM
"Nigeria's best current forward and likely starter up the front is Aide Brown Ideye. He is best priced 3/1 to be first player to score vs the hapless part time Pacific Islanders, and best priced 1/2 to score anytime. Bet365 are offering 3/1 and a third the odds each way to score anytime." I tried to work out EV for backing him e/w as FGS, and started by assuming anytime GS was priced correctly with margin added. Therefore assumed true odds of him scoring anytime are 48% assuming £1 e/w, so (-2*0.52) etc represents 52% of time he fails to score and we lose our stake... =(-2*0.52)+(0*(0.48*(1-H2)))+(4*(0.48*H2)) cell H2 we input % that he is FGS when scoring IF (big if) I've done this correctly we break even only if he scores first in 55% or more of the matches in which he is a goal scorer If you start by assuming the odds we get on our place part of our each way price is the correct one, you are a long way on the road to proving the bet is terrible. BUT we only got evens on the anytime scoring because we are backing each way, and they are using standard pricing rather than adjusting to this particular match. The odds quoted elsewhere on him scoring anytime are either 1/2 or worse. That is equivalent to scoring in 67% of matches. Obviously 67% is likely to be a bit too high, but the true odds are going to be a lot closer to that than 48%.Title: Re: Mathematics and Betting ThreadPost by: Dubai on June 17, 2013, 03:00:23 PM
He is probably around 7/2 15/4 1st gs and 8/13 4/7 anytime
Title: Re: Mathematics and Betting ThreadPost by: Doobs on June 17, 2013, 03:06:30 PM
He is probably around 7/2 15/4 1st gs and 8/13 4/7 anytime I did a calc last night and think the bet was still quite profitable if the true odds were 7/2 and 4/6. Am rushing out, so can't check this now Title: Re: Mathematics and Betting ThreadPost by: RickBFA on June 19, 2013, 11:28:35 AM
This looks like a great thread. Really useful, thanks.
Looking forward to your thoughts on dirty each ways. Title: Re: Mathematics and Betting ThreadPost by: MahoganyVic on June 20, 2013, 11:46:20 PM
Probably a stupid question, but how do you work out the odds of getting a winner if have several horses in the race/ event.
Eg Looking at the British Open golf odds on betfair, is there a quick way to calculate the rough odds of having an English winner? Title: Re: Mathematics and Betting ThreadPost by: doubleup on June 21, 2013, 09:36:59 AM
for every player 1/betfair odds added up eg
player 1 betfair 10 player 2 10 player 3 10 1/10 + 1/10 + 1/10 = 3/10 = .3 probability to get back to betfair odds 1/.3 = 3.33 Title: Re: Mathematics and Betting ThreadPost by: MahoganyVic on June 21, 2013, 09:42:59 AM
Cheers
Title: Re: Mathematics and Betting ThreadPost by: Omm on December 13, 2013, 08:50:05 AM
Tal kindly put this link up on TFT to help those of us who need it, big thank you to doobs for spending the time to start it in the first place. No doubt this will be a massive help for a lot of us.
I have a question about EV in sports betting. I really wanted to know how important or relevant it is? I was reading an article which gave an explanation of how to work it out: 1. Find the decimal odds for each outcome (win, lose, draw) 2. Calculate the potential winnings for each outcome by multiplying your stake by the decimal, and then subtract the stake. 3. Divide 1 by the odds of an outcome to calculate the probability of that outcome 4. Substitute this information into the above formula. For example, when Manchester United (1.263) play Wigan (13.500), with a draw at 6.500, a bet of $10 on Wigan to win would provide potential winnings of $125, with the probability of that happening at 0.074 or 7.4%. The probability of this outcome not occurring is the sum of Man Utd and a draw, or 0.792 + 0.154 = 0.946. The amount lost per bet is the initial wager – $10. Therefore the complete formula looks like: (0.074 x $125) – (0.946 x $10) = -$0.20 The EV is negative for this bet, suggesting that you will lose an average of $0.20 for every $10 staked. From that I ran a few examples myself and it seems that the odds have to be evens on both sides for the EV to be positive. So for example If I bet on NFL where the prices are generally 10/11 or 1.91. Using the equation above my EV is negative showing I will lose on average £0.47 for every £10 staked. So how does that compare to the reality of the situation, is it really a case that in the long run on this type of bet am expected to lose? Does that reflect on whether I should place the bet or not? Is there a need to be aware of the EV of bets? Title: Re: Mathematics and Betting ThreadPost by: doubleup on December 13, 2013, 09:27:32 AM
Each books individual odds are going to show a decent % in the books favour. But you should be taking the best odds from the whole market. If the best odds still show a high -ev, it might be wise to swerve that kind of bet unless you are fairly certain that the odds are wrong. Title: Re: Mathematics and Betting ThreadPost by: Doobs on January 19, 2014, 07:43:19 PM
Bump. Free bet stuff is in the 2nd post in this thread.
Title: Re: Mathematics and Betting ThreadPost by: Doobs on March 12, 2014, 03:33:46 PM
Bumped for discussion of arbing thread bets, including using golf to arb those bets, including the issues we have doing so with HilliamBills
Title: Re: Mathematics and Betting ThreadPost by: GreekWay on March 12, 2014, 11:54:33 PM
Only just seen this. Great post Doobs.
Some important eye-openers. Really helpful. I always hated advanced maths but you make them look really easy. Thank you very much Sir. Title: Re: Mathematics and Betting ThreadPost by: Simon Galloway on March 13, 2014, 01:39:54 AM
For dirty each ways, I thought the easiest maths (and the choice of nits) was to just calculate the cost of unloading the win part (and unload the win part) and compare your remaining place only bet (after factoring in the disposal cost) with betfair place market?
Title: Re: Mathematics and Betting ThreadPost by: Doobs on March 13, 2014, 02:08:03 AM
I never got round to doing the dirty each way bit, sorry.
May as well answer this whilst here Looking ahead to tomorrow's Cheltenham action, Ladbrokes are taking on Annie Power but vowing to refund stakes as a free bet if Willie Mullins' mare wins the race they sponsor, the World Hurdle.Annie Power is the big-race favourite at 6/4 at present, although Ladbrokes say they will go up with 9/4 in the morning. The money-back offer will go live at 0900 GMT with a maximum of £25 to be refunded. The firm's David Williams said: "Annie Power is the stand out horse on day three and we're dangling an enormous carrot with this money back pledge framed around her winning. "We're thrilled to bits that the showdown with Big Buck's is on in what we believe is the clash of the week and we fully expect this offer to trigger the busiest build-up to the racing we've seen all week across all our key channels." Annie Power's main rival is four-time winner Big Buck's, about whom Boylesports are currently offering 4/1. So if they go for a refund offer which of the two is worth it? Backing Annie Power or Big Bucks? Discuss. I believe that is a question for the expert Mr. Doobs. Smiley Here is the maths behind the shall I back Big Bucks or Annie Power question under the Ladbrokes offer. Ladbrokes are offering 9/4 Annie Power or 3/1 Big Bucks but with a refund if Annie Power wins. Assuming you can bet £25 on each. The expected return from the Annie Power bet can be calculated as follows. If Annie Power wins, you get £25 x 13/4 as a return ie £81.25. Assuming Betfair is the true odds, the chance of that happening is 1/2.65. 81.25/2.65 = £30.66 The expected return from the big Bucks bet can be calculated as follows. They only offer 3/1 on Big Bucks, so if it wins you get £100. Assuming Betfair is the true odds, the chance of that happening is 1/5.15. 81.25/5.15 = £19.42. You also get your £25 back as a free bet if Annie Power wins. I assume free bets aren't really worth £25, as you usually lose a bit when you place them. This applies if you arb or just find a nice bet. Assuming we lose 10% of the value which is fairly typical. So free bet is worth chance of Annie Power winning x £25 x 0.9 = 22.5/2.65 = £8.49. So total value of Big Bucks bet is £19.42 + £8.49 = £27.91. So to me it is absolutely clear the best plan is to just back Annie Power at 9/4. That also is much simpler, as you don't have to use a free bet, set up an arb etc. Title: Re: Mathematics and Betting ThreadPost by: doubleup on March 13, 2014, 09:25:59 AM
I never got round to doing the dirty each way bit, sorry. you were overawed by the power of excel https://docs.google.com/file/d/0Byg8Wbbo5p2ucDN2WVdueENUYzA/edit?pli=1 Title: Re: Mathematics and Betting ThreadPost by: Doobs on March 17, 2014, 04:06:12 PM
I really have a couple of time issues at the minute. Friday I tend to play poker late, and my kids can be up as early as 6 in the morning with the brighter mornings. I rarely get woken after 7. People can look back and see what time I put the Hills bets up and it must generally be 2 or 3 in the morning.
I can put up free bets by scanning the Hills prices in things I know well, and checking against Betfair. I can probably do this in 10 or 15 minutes and put something sensible up. I realise this isn't ideal, but if I was to look for the very best Hills bet it will genuinely take me much longer than that. I think together with the free bet and doing the top thing I can make a fiver or so from each free bet. The extra I can get from doing a much better scan of Hills is going to gain much less than the initial fiver or so, and the gain can't be much more than a pound or two. On the arbbing thing, I have no tools for arbbing, so say I wanted to arb a golfer, I'd probably have to look through at least 3 golf tournaments a week (maybe 500 golfers) to find the best bet. That seems a big undertaking to me, even if I could cut some out quickly. If I was to add in some football scores, the work I would have to go through to get that extra pound or two seems like a lot of work to make very little gain. I appreciate I may be able to google around and take somebody else's Hills arb of the week for the best way to use a free bet that week, but that isn't something I am comfortable with or a route I want TfT to take. I am not sure why I am the only one who gets the you don't want to do it like that treatment. When somebody puts up a Scottish footballer to score anytime, nobody ever suggests that we back a golfer and lay it off on Betfair instead. It doesn't seem to cross people's minds apart from with the free bets. Anybody any thoughts? Title: Re: Mathematics and Betting ThreadPost by: TightEnd on March 17, 2014, 04:18:19 PM
I've no complaints about the maths or the free bets
The issue is whether to embrace variance (we currently put a free bet on something "at a price") or reduce it (we lay off on betfair exactly what we back with the free bet) I think the weakness we have is that the selection of the item for the free bet is often rushed, sometimes last minute panicky and often doesn't have the same level of thought or written research as some of the original bets. This isn't a criticism of doobs, it applies to tikay's time management and the reluctance (it seems) for a range of people to put forward ideas for free bets in good time At the end of the day though with a higher variance approach you are going to get low returns for long spells with the free bets at 10-1+ shots. I do think the selection of some of those can be improved, or more process driven (ie not last minute "it has to be used today, what on?"). I think this is sonour's point On arbbing, doobs is saying it "seems a big undertaking to me" whilst arrboy says its virtually no work at all to guarantee turning a free bet into cash at a 95% rate. I've no idea which applies but I suspect with tikay (no offence meant) its got to mean misclick potential, more demands on his time and probably more thread admin Title: Re: Mathematics and Betting ThreadPost by: arbboy on March 17, 2014, 04:30:13 PM
I very rarely encounter free bets where the stake isn't refunded as the vast majority of my business is done on bf. My only real experience of them is when opening new accounts with firms and because of the crazy ladbrokes promo on the chelsea v man u game when i ended up with 60 £25 freebets which i had 7 days to use and i just wanted the least swingy way to effectively convert them back to cash. I didn't find it an issue finding numerous big prices at ladbrokes which i could lay at shorter prices on bf to convert these back into cash.
The other option was to have £1500 invested in 20/1-100/1 shots and just roll with it and potentially iron out £1500 in real cash effectively on events i didn't especially have a view on but i was forced to invest due to the 7 day expiry date of the free bets. I wouldn't have backed any of the selections with my own cash if i didn't have the free bets as i had no strong view on the events. Therefore i just saw it as a manner to convert free bets into cash with the least potential variance as i had made plenty of cash already out of the promotion. Title: Re: Mathematics and Betting ThreadPost by: doubleup on March 17, 2014, 04:45:48 PM
The thing is though that a "perfect" arb bet should be a perfect bet to keep. Arbing is just a tool to reduce variance that comes at a cost. The solution might be to have a process for time pressure situations eg look at the correct score market for the TV high liquid matches. Or even just do a shout out in the thread for bets at 10s+ same price in liquid betfair markets. Title: Re: Mathematics and Betting ThreadPost by: arbboy on March 17, 2014, 04:59:05 PM
The thing is though that a "perfect" arb bet should be a perfect bet to keep. Arbing is just a tool to reduce variance that comes at a cost. The solution might be to have a process for time pressure situations eg look at the correct score market for the TV high liquid matches. Or even just do a shout out in the thread for bets at 10s+ same price in liquid betfair markets. The perfect arb bet is to back a 5/1 shot at 11/2 and lay it at 9/2. ie both bets individually are both value. With regard to my 100/1 'first scoring play in the superbowl' i backed 100/1 and laid it at 55/1 on bf with 2 of the £25 free bets i had. I have no idea whether the 100/1 is value or laying 55/1 on bf is value. I would imagine both trades are value trades and i can make them both without any risk to myself and no swings to worry about. I would imagine the correct price is somewhere between the two and at the same time convert a £25 free bet into actual cash with a profit on top with no risk at all. Title: Re: Mathematics and Betting ThreadPost by: doubleup on March 17, 2014, 05:14:27 PM
point taken but usually the error is on one side and in the context of this discussion we are usually looking for a bet that is as close to ev neutral as possible. Title: Re: Mathematics and Betting ThreadPost by: BorntoBubble on April 02, 2014, 09:01:50 PM
Coral had a mobile offer today of 2/1 for hazard or oscar to score anytime.
The best prices were 5/1 and 4/1 I think. So if i just backed them at the best prices I get £8 on at 4/1 and £10 on at 5/1 I win £40 if either score and £80 if both score. Yet if i place £18 with coral i get £36? Have I got the maths right here and this is a shocking offer? Or is there something im missing. If the odds of two individual events are priced at 5/1 and 4/1 what is the calculation for working out either or happening is that using that nCr calculation? I probably should know this but my brain is doing a brain fart. Why if these calculations are correct to bookies send out these offers if they are horrific? Title: Re: Mathematics and Betting ThreadPost by: rfgqqabc on April 02, 2014, 09:07:35 PM
Coral had a mobile offer today of 2/1 for hazard or oscar to score anytime. The best prices were 5/1 and 4/1 I think. So if i just backed them at the best prices I get £8 on at 4/1 and £10 on at 5/1 I win £40 if either score and £80 if both score. Yet if i place £18 with coral i get £36? Have I got the maths right here and this is a shocking offer? Or is there something im missing. If the odds of two individual events are priced at 5/1 and 4/1 what is the calculation for working out either or happening is that using that nCr calculation? I probably should know this but my brain is doing a brain fart. Why if these calculations are correct to bookies send out these offers if they are horrific? The word boost gets people excited. Lol maffs etc. Title: Re: Mathematics and Betting ThreadPost by: BorntoBubble on April 02, 2014, 09:12:57 PM
Coral had a mobile offer today of 2/1 for hazard or oscar to score anytime. The best prices were 5/1 and 4/1 I think. So if i just backed them at the best prices I get £8 on at 4/1 and £10 on at 5/1 I win £40 if either score and £80 if both score. Yet if i place £18 with coral i get £36? Have I got the maths right here and this is a shocking offer? Or is there something im missing. If the odds of two individual events are priced at 5/1 and 4/1 what is the calculation for working out either or happening is that using that nCr calculation? I probably should know this but my brain is doing a brain fart. Why if these calculations are correct to bookies send out these offers if they are horrific? The word boost gets people excited. Lol maffs etc. Just it was so bad (using my maths) I assumed i got it wrong. Sad that im sat here looking at maths on betting rather than getting a maths degree. Title: Re: Mathematics and Betting ThreadPost by: Tal on April 02, 2014, 11:20:04 PM
You mean £8 at 5/1 and £10 at 4/1, right?
Title: Re: Mathematics and Betting ThreadPost by: BorntoBubble on April 02, 2014, 11:28:25 PM
Title: Re: Mathematics and Betting ThreadPost by: doubleup on April 02, 2014, 11:32:36 PM
with this kind of bet just work out how much you need to bet to
return £100 on both bets so £20 @ 4-1 gives you a £100 return and £16.67 @ 5-1 gives you a £100 return.If you add them together you get £36.67 bet will get you £100 return if either of them win -- in comparison to £33.33 bet @ the 2-1 getting you same £100 if either win. So the 2-1 is better as you only lose £33.33 if the bet fails and you get the same return if it wins. Title: Re: Mathematics and Betting ThreadPost by: doubleup on April 03, 2014, 12:33:49 AM
oops misread your problem - obv a bad offer as you can get the double payout
Title: Re: Mathematics and Betting ThreadPost by: doubleup on April 03, 2014, 11:13:29 AM
ok having another look at it with fresh eyes, think I have it now.... Your method is wrong because I win £40 if either score isn't correct as you haven't deducted the loss from the other bet.ie when you win the £8 at 5-1, you lose the £10 at 4-1, so you actually just win £30. Back to my above post comparing the returns you get £36.67 bet will get you £100 return if either of them win with the two separate bets in comparison to £33.33 bet @ the 2-1 getting you same £100. I had a mess around with a Poisson calculator (assuming that the 5-1 and 4-1 odds are accurate) to try and find an approximate % where both players score and it seems to be about 3% or so So if we say roughly 66% neither scores, 31% either player scores and 3% both score For our stake of £36.67 we get nil 66% £100 31% = £31 £200 3% = £6 So a return of £37 If we put the same £36.67 on the offer @ 2-1 our return would be £110 34% = £37.40 So after all that really not much in it. Title: Re: Mathematics and Betting ThreadPost by: JaffaCake on April 28, 2014, 05:47:29 PM
I am gonna reread this thread but if it hasn't been covered, this is what I posted on TfT:
"Red/Argue....how do u decide what's bes, 10/11 at one total or evens at a point higher or whatever. Is there proper maths behind it or is it a feel thing? Same for if say we can back a horse at 16/1 ew with 4 places or 14/1 ew with 5 places (or whatever). Is that a question best asked on the maths thread?" Also wanted to add, quite often I look at basketball handicaps, one firm will be 10/11 +6.5, another evens +7, another 8/11 +10 etc etc Title: Re: Mathematics and Betting ThreadPost by: arbboy on April 28, 2014, 05:49:38 PM
Stu is def your man for the maths side of buying points etc in nba.
Title: Re: Mathematics and Betting ThreadPost by: redarmi on April 28, 2014, 06:30:36 PM
Posted this in TFT:
"The NBA are fairly easy to work out. Each individual point is likely to land a certain amount of time so has a value. In the NBA for a regular pointspread most half points are worth about 0.05 in decimals. So-3 2.0 is about the same as -3.5 2.05. They differ slightly as some pointspreads are more likely to fall and I have charts for them but as a rule 0.05 is fine. As for horseracing places - feel is better. There is some very heavy academic work on how likely a horse is to place and nobody has "solved" it as such but if you look at enough of them you get a reasonably good feel. An okay rule of thumb is if you turn the prices into percentages so in the case you said. The place price at 14/1 is 7/2 (14/4) or 22.22% for 5 places. For 4 places it is 4/1 (16/4) or 20%so they are effectively they are saying there is a 2.22% chance of your horse coming 5th (22.22%-20%) which is about a 45/1 shot so ask yourself would I back this horse to come fifth at 45/1? That sounds like value to me so I would take the extra place and even if I only thought it was fair value I would take it because the extra place reduces my variance. Does that make sense?" I didn't actually address your question on nba totals though. It is probably about 0.04 for NBA totals as a rule. If you have a pinnacle account then log into your account and look to see what they charge and they are pretty much spot on. If you find a book offering much different to what pinnacle offer then that book is wrong and you have a bet. If you want the NBA pointspreads I have a chart I did one time but I don't think I ever did the totals because they don't vary as much so 0.03-0.04 works well. Title: Re: Mathematics and Betting ThreadPost by: Longines on April 29, 2014, 06:56:55 PM
I've been thinking about this spread betting question and it's making my head hurt, wonder if anyone can help.
On average, 0.22 penalties are scored in each champions league game so if it was a normal bet then in theory we fill our boots when offered 5/1 or better on a penalty being scored. Assuming the time that the penalties are scored is random and evenly spread throughout the 90 minutes* how do you determine the buy or sell point at which a bet is strictly mathematically +EV? *big assumption, I know. Title: Re: Mathematics and Betting ThreadPost by: doubleup on April 29, 2014, 07:34:30 PM
4-1 or better surely
[/nitmanship] edit although it occurs to me that some matches have more than one penalty, so really the relevant stat is the % of matches with penalties Title: Re: Mathematics and Betting ThreadPost by: redarmi on April 29, 2014, 07:40:45 PM
I've been thinking about this spread betting question and it's making my head hurt, wonder if anyone can help. On average, 0.22 penalties are scored in each champions league game so if it was a normal bet then in theory we fill our boots when offered 5/1 or better on a penalty being scored. Assuming the time that the penalties are scored is random and evenly spread throughout the 90 minutes* how do you determine the buy or sell point at which a bet is strictly mathematically +EV? *big assumption, I know. Is all of the info in this post? Not sure how it is a spread betting question so not sure if you have missed something out given you talk about buy/sell etc. Title: Re: Mathematics and Betting ThreadPost by: Longines on April 29, 2014, 07:57:20 PM
Is all of the info in this post? I thought it was... To take it to the extremes, if the spread is 0-1 then I think we should buy as the average penalty will be scored after 45 minutes and we win 44x our stake. If the spread is 88-89 then I think we should sell for similar reasons. However if the spread is say 16-18 I'm trying to work out if it that is +EV to either buy or sell? Title: Re: Mathematics and Betting ThreadPost by: redarmi on April 30, 2014, 01:16:54 AM
Ahhh so the market you are questioning is penalty minutes? You can use poisson distribution to work out the chances of 0,1,2,3 etc penalties. In this case there is roughly an 80.25% chance of no penalties scored, 17.65% and a 1.9% chance of two penalties. So as a shorthand way to get there I would ignore the chances of 2 penalties and then just take the 90(minutes) *.1765 which gives you a midpoint of 15.88. I would then add a couple of points back for the chances of 2+ penalties and round it up to give a midpoint of 18 or so. So if the spread was 16-18 there isn't really any value in it. I do think that the assumptions are wrong though. Goals are not evenly split between halves (they are generally 45/55 split) and for the same reasons penalties are more likely to come in the second half. If anything I would think the distribution would be more skewed to the 2nd half as refs are less keen to give away early penalties I would think. You could put together a spreadsheet to work it out but my guess would be that back of the envelope calcs like this would largely prove there was no value. I would only be more inclined to put the work in if I was fairly sure there was value as the spread boys tend to be very good at this kind of stuff.
Title: Re: Mathematics and Betting ThreadPost by: TheDazzler on May 31, 2014, 04:29:10 PM
At what point does playing the Euromillions become +EV?
I know that's it's ~116 million to one to win the jackpot with 1 line and as it's 2 euros a ticket you need 232 million in the jackpot (and of course you'd need to be the only winner) but there is obv all the smaller prizes to take into account. They can vary in size so I guess you can't come up with an exact number but has anyone worked this out roughly? At ~120 million jackpot, are we maybe approaching neutral EV? Title: Re: Mathematics and Betting ThreadPost by: doubleup on September 29, 2014, 03:05:45 PM
How much ev on the win part of the bet can we afford to give up when the place part of the bet is clearly +ev? I do it by intuition only at the moment. Here's a calculator https://docs.google.com/file/d/0Byg8Wbbo5p2ucDN2WVdueENUYzA/edit?usp=sharing you have to download it - you can't put the data in on google docs For anyone who looks for EW opportunities and doesn't have excel, this calculator is now online http://www.sportspreadsheet.com/EachwayCalc.html Title: Re: Mathematics and Betting ThreadPost by: redarmi on September 29, 2014, 06:05:26 PM
Something has been puzzling me recently and this thread might be just the place. I generally use Kelly Criteria for my staking, or a portion of it, but these days I am doing a lot more racing bets at each way where for the win part I have a neutral or negative expectation and all of my expectation is in the win part. How would you deal with that based on the fact that the bookies make me bet the same amount on the win as on the place element of the bet? It is okay to work out the overall expectation and base my staking on that or is that bad?
Title: Re: Mathematics and Betting ThreadPost by: doubleup on September 29, 2014, 06:16:09 PM
I actually posted the same Q in a couple of places and got no responses. I would guess that you should calc the overall EV and then stake on the win odds, tho that's clearly overstaking on the win and understaking on the place. Title: Re: Mathematics and Betting ThreadPost by: Doobs on September 29, 2014, 07:23:00 PM
I actually posted the same Q in a couple of places and got no responses. I would guess that you should calc the overall EV and then stake on the win odds, tho that's clearly overstaking on the win and understaking on the place. I'd stake on the combined win and place bet. You have worked out the EV on the combined bet. I think it maybe should be more as the bet should have lower volatility than a win bet. But you can counter that by saying that the 2nd bet is related to the first so you don't really want to be doubling your win stake. Think you are probably fine just meeting half way and working it as a bet of 1.5x the win stake? All top of my head without any maths, and never really thought about it before. Title: Re: Mathematics and Betting ThreadPost by: redarmi on September 29, 2014, 07:59:10 PM
Yes all makes sense and a few others have said similar to me privately. My biggest concern is not overstaking and it is pretty unlikely I would overstake as I am pretty conservative with my staking. Thanks for the responses.
Title: Re: Mathematics and Betting ThreadPost by: sonour on March 16, 2015, 01:41:46 AM
Hi Doobs,
Could you help with the McCoy to ride a winner problem I struggled with on TFT please. 9/2 13/2 10/1 11/1 20/1 I think you have to invert the odds and multiply them together to get the odds of him not riding a winner and then take this answer away from 1 ? But I'm still not sure how to do it. I'll have another stab, 1.22 x 1.15 x 1.1 x 1.09 x 1.05 = 1.76 100 / 1.76 = 56.8 % 100 / 43.2 % = 2.31 decimal odds. Did I do any better this time ? :) Your help would be appreciated. Thanks Title: Re: Mathematics and Betting ThreadPost by: Larry David on March 16, 2015, 03:05:47 AM
10/10 Correct. All about the INVERTED T Carol
But yes correct. Title: Re: Mathematics and Betting ThreadPost by: doubleup on March 16, 2015, 08:39:21 AM
I would do the calc in probabilities ie 1-(1/7.5) = .87 1-1/5.5 = .82 etc then final probability 1- (.87x.82x.92x.91x.95) but the same thing - i think the actual odds are 2.287 because there is a lot of rounding up using two decimals Title: Re: Mathematics and Betting ThreadPost by: sonour on March 16, 2015, 11:51:08 AM
Thanks. That was going to be my next question. I shouldn't have to convert to percentages and then back to decimal odds.
So if the decimal odds for an event occurring are say 3.5 then the decimal odds for it not occurring are :- 1 / 1 - ( 1 / 3.5 ) Is that correct ? Title: Re: Mathematics and Betting ThreadPost by: doubleup on March 16, 2015, 12:27:34 PM
yes that is correct. As I said I tend to use probabilities most of the time for any sums, mostly because when some thing is over my head there is usually a formula on wikipedia or the like that uses probabilities rather than odds. Title: Re: Mathematics and Betting ThreadPost by: Doobs on March 16, 2015, 09:34:31 PM
All looks correct. I tend to just bang things in spreadsheets so it is easier to calc and easier to spot mistakes. I know I got slated for it, but it is important to realise when these maths things fall apart. In this case I think some of the McCoy prices were clearly too short (the last one really looked an 8/1 chance to me etc). The 3/1 bf sportsbook still looked a great bet (I got close to 2/1 after adjusting 3 prices), but I so decided the 8/11 hills on no winners was a bet too. 8/11 on a 1/2 bet is good too. Made me think they probably hadn't adjusted properly for the circumstances too. Ofc I worked this out long after the day had finished.
I will try and put something up about each way betting on here this week. Keep saying I will but never get round to it. Title: Re: Mathematics and Betting ThreadPost by: Karabiner on March 16, 2015, 09:50:03 PM
Who's Carol?
Title: Re: Mathematics and Betting ThreadPost by: tikay on March 16, 2015, 09:55:08 PM
Who's Carol? Think it was a reference to the girl who used to be on Countdown, before she had a makeover and went all posh? Title: Re: Mathematics and Betting ThreadPost by: Larry David on March 16, 2015, 10:06:32 PM
Who's Carol? Think it was a reference to the girl who used to be on Countdown, before she had a makeover and went all posh? You don't miss a trick MR T Title: Re: Mathematics and Betting ThreadPost by: Doobs on May 14, 2015, 12:25:45 PM
I have been meaning to put a post up here about each way betting more or less since I started.
First things first, I think betting a classic dirty each way using an online account is really stupid. By classic dirty each way race I mean one with an odds on favourite and a few rags. Firstly you often get mugged on the win price with the bookies, so you will find yourself taking 5/1 on an 8/1 chance on the machine. Secondly the very fact they are offering 5/1 on an 8/1 chance means that they are very aware that people are going to try and mug them on this race. The end result is that you will often lose your account and not even get much value on the bet that cost you it. Where you can make money and keep an account a bit longer is betting on good each way races. So what makes a good each way race mathematically? I am going to put togethether a couple of examples to show the difference between betting each way in a bad each way race and a good one. Race 1 is a good each way race, we have 17 runners and get quarter the first 4.We manage to find a runner that is 16/1 and bang on that price on Betfair. That means it has a 1 in 17 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 16/1 to finish in any position you choose in the race. So he is going to be 16/1 to finsh 5th, 12th or 17th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. As we know he has a 1/17 chance of coming in any position, we can estimate the odds he finishes in the first 4 places as 4/17. So if I was to offer you correct odds on the place as 13/4 or just over 3/1. Your average bookie will pay you 4/1. That is a near 18% uplift on the place terms from what they should offer you. If I could spend my life finding 16/1 chances in races like this that were 16/1 on the machine and had no horse picking skills at all I'd make 9% return on my money each time I make an each way bet like this in the long run. Race 2 is a bad each way race, we have 11 runners and get a fifth the first 3.Like race 1, we manage to find a runner that is 10/1 and bang on that price on Betfair. That means it has a 1 in 11 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 10/1 to finish in any position you choose in the race. So he is going to be 10/1 to finsh 3rd, 6th or 11th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. This should all be very familiar. As we know he has a 1/11 chance of coming in any position, we can estimate the odds he finishes in the first 3 places as 3/11. So if I was to offer you correct odds on the place as 8/3 or just under 3/1. Your average bookie will pay you 2/1. That is just over an 18% haircut on the place terms from what they should offer you. If I could spend my life finding 10/1 chances in races like this that were 10/1 on the machine and had no horse picking skills at all I'd lose 9% of money each time I make an each way bet in the long run. This is really crucial information to know if you are going to be putting a lot of each way bets on in the future. If you do find that 10/1 chance in that 11 runner race, you just have to stop backing it each way. Backing 10/1 chances each way is such an ingrained habit with punters that it might be hard to lose, but you should always look at the number of runners in the race before backing it each way. Each time that horse finishes 2nd and 3rd in that 11 runner race, 95% of punters will be kicking themselves saying they should have backed it each way. Many of your friends will happily point this out to you. You need to be one of the 5% who knows you absolutely shouldn't have and usually it isn't even close. Title: Re: Mathematics and Betting ThreadPost by: doubleup on May 14, 2015, 12:46:46 PM
Without making things too complicated, remember that you can back win and place on the exchanges, so if you think the betfair win price is value, the betfair place price will presumably be value as well. With the added wrinkle that in the circumstances doobs outlined, even more value can be found from a bookmaker. Also some horses eg unknown on the going, first time blinkers, might have a win or flop profile so not really suitable for place backing. Here is a calculator to compare bookies and exchanges prices and article about it. http://www.sportspreadsheet.com/eachway.html http://www.sportspreadsheet.com/eachwaycalc.html Title: Re: Mathematics and Betting ThreadPost by: tikay on May 14, 2015, 12:47:25 PM
Brilliant stuff, thanks for sharing. Title: Re: Mathematics and Betting ThreadPost by: arbboy on May 14, 2015, 12:57:31 PM
I have been meaning to put a post up here about each way betting more or less since I started. First things first, I think betting a classic dirty each way using an online account is really stupid. By classic dirty each way race I mean one with an odds on favourite and a few rags. Firstly you often get mugged on the win price with the bookies, so you will find yourself taking 5/1 on an 8/1 chance on the machine. Secondly the very fact they are offering 5/1 on an 8/1 chance means that they are very aware that people are going to try and mug them on this race. The end result is that you will often lose your account and not even get much value on the bet that cost you it. Where you can make money and keep an account a bit longer is betting on good each way races. So what makes a good each way race mathematically? I am going to put togethether a couple of examples to show the difference between betting each way in a bad each way race and a good one. Race 1 is a good each way race, we have 17 runners and get quarter the first 4.We manage to find a runner that is 16/1 and bang on that price on Betfair. That means it has a 1 in 17 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 16/1 to finish in any position you choose in the race. So he is going to be 16/1 to finsh 5th, 12th or 17th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. As we know he has a 1/17 chance of coming in any position, we can estimate the odds he finishes in the first 4 places as 4/17. So if I was to offer you correct odds on the place as 13/4 or just over 3/1. Your average bookie will pay you 4/1. That is a near 18% uplift on the place terms from what they should offer you. If I could spend my life finding 16/1 chances in races like this that were 16/1 on the machine and had no horse picking skills at all I'd make 9% return on my money each time I make an each way bet like this in the long run. Race 2 is a bad each way race, we have 11 runners and get a fifth the first 3.Like race 1, we manage to find a runner that is 10/1 and bang on that price on Betfair. That means it has a 1 in 11 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 10/1 to finish in any position you choose in the race. So he is going to be 10/1 to finsh 3rd, 6th or 11th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. This should all be very familiar. As we know he has a 1/11 chance of coming in any position, we can estimate the odds he finishes in the first 3 places as 3/11. So if I was to offer you correct odds on the place as 8/3 or just under 3/1. Your average bookie will pay you 2/1. That is just over an 18% haircut on the place terms from what they should offer you. If I could spend my life finding 10/1 chances in races like this that were 10/1 on the machine and had no horse picking skills at all I'd lose 9% of money each time I make an each way bet in the long run. This is really crucial information to know if you are going to be putting a lot of each way bets on in the future. If you do find that 10/1 chance in that 11 runner race, you just have to stop backing it each way. Backing 10/1 chances each way is such an ingrained habit with punters that it might be hard to lose, but you should always look at the number of runners in the race before backing it each way. Each time that horse finishes 2nd and 3rd in that 11 runner race, 95% of punters will be kicking themselves saying they should have backed it each way. Many of your friends will happily point this out to you. You need to be one of the 5% who knows you absolutely shouldn't have and usually it isn't even close.Awesome post esp the bit about always backing 10/1 or 16/1 shots ew. It is the biggest leak of all amongst rec punters. Even if they have an edge on the win part of the bet because they are a good judge they literally set fire to that edge (and more on top usually) by betting it ew and taking on maths which you just can't beat long term. As i have said before probably the best 100 ew bets i have ever had in my life i would say the vast majority of them have been shorter than 4/1 and 50% of them shorter than 6/4 and many decent odds on. Just think of Doob's bolded statement everytime you want to back that 16/1 shot ew because you always have or 'it is a good ew bet' blah blah. Next time you go racing just do one thing when you are in the betting ring and you will realise which races are like this. Watch and listen to the old school bookmakers in the ring. If they are shouting 'wiiiiiiiiiiinnnnnnnnnnn or eachhhhhhhhhhhh way' to try and attract your business you can gtd that it is a terrible ew race to bet in, like race 2, in the example but the race offers obviously them a huge edge hence why they are so keen to 'sell' you an ew bet. If it is like race 1 they won't be so keen to be selling you an ew bet if they are even offering ew terms on the race. Title: Re: Mathematics and Betting ThreadPost by: Doobs on May 14, 2015, 01:02:16 PM
Without making things too complicated, remember that you can back win and place on the exchanges, so if you think the betfair win price is value, the betfair place price will presumably be value as well. With the added wrinkle that in the circumstances doobs outlined, even more value can be found from a bookmaker.Also some horses eg unknown on the going, first time blinkers, might have a win or flop profile so not really suitable for place backing. Here is a calculator to compare bookies and exchanges prices and article about it. http://www.sportspreadsheet.com/eachway.html http://www.sportspreadsheet.com/eachwaycalc.html I assume you are taliking a good each way race in the bit in bold. With a bad each way race it might be true, but you't have to be such a good tipster to get over that 18% handicap on the place terms. And of course you wouldn't need to do that if you just backed the win. Of course there are circumstances that make one horse a better each way horse than another, for instance Abseil is first time out in the 3.45 which I suspect is a bit of a negative for place betting. But 14/1 looks a decent price and the maths is still good. Title: Re: Mathematics and Betting ThreadPost by: peejaytwo on May 14, 2015, 01:15:15 PM
I have been meaning to put a post up here about each way betting more or less since I started. First things first, I think betting a classic dirty each way using an online account is really stupid. By classic dirty each way race I mean one with an odds on favourite and a few rags. Firstly you often get mugged on the win price with the bookies, so you will find yourself taking 5/1 on an 8/1 chance on the machine. Secondly the very fact they are offering 5/1 on an 8/1 chance means that they are very aware that people are going to try and mug them on this race. The end result is that you will often lose your account and not even get much value on the bet that cost you it. Where you can make money and keep an account a bit longer is betting on good each way races. So what makes a good each way race mathematically? I am going to put togethether a couple of examples to show the difference between betting each way in a bad each way race and a good one. Race 1 is a good each way race, we have 17 runners and get quarter the first 4.We manage to find a runner that is 16/1 and bang on that price on Betfair. That means it has a 1 in 17 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 16/1 to finish in any position you choose in the race. So he is going to be 16/1 to finsh 5th, 12th or 17th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. As we know he has a 1/17 chance of coming in any position, we can estimate the odds he finishes in the first 4 places as 4/17. So if I was to offer you correct odds on the place as 13/4 or just over 3/1. Your average bookie will pay you 4/1. That is a near 18% uplift on the place terms from what they should offer you. If I could spend my life finding 16/1 chances in races like this that were 16/1 on the machine and had no horse picking skills at all I'd make 9% return on my money each time I make an each way bet like this in the long run. Race 2 is a bad each way race, we have 11 runners and get a fifth the first 3.Like race 1, we manage to find a runner that is 10/1 and bang on that price on Betfair. That means it has a 1 in 11 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 10/1 to finish in any position you choose in the race. So he is going to be 10/1 to finsh 3rd, 6th or 11th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. This should all be very familiar. As we know he has a 1/11 chance of coming in any position, we can estimate the odds he finishes in the first 3 places as 3/11. So if I was to offer you correct odds on the place as 8/3 or just under 3/1. Your average bookie will pay you 2/1. That is just over an 18% haircut on the place terms from what they should offer you. If I could spend my life finding 10/1 chances in races like this that were 10/1 on the machine and had no horse picking skills at all I'd lose 9% of money each time I make an each way bet in the long run. This is really crucial information to know if you are going to be putting a lot of each way bets on in the future. If you do find that 10/1 chance in that 11 runner race, you just have to stop backing it each way. Backing 10/1 chances each way is such an ingrained habit with punters that it might be hard to lose, but you should always look at the number of runners in the race before backing it each way. Each time that horse finishes 2nd and 3rd in that 11 runner race, 95% of punters will be kicking themselves saying they should have backed it each way. Many of your friends will happily point this out to you. You need to be one of the 5% who knows you absolutely shouldn't have and usually it isn't even close.Awesome post esp the bit about always backing 10/1 or 16/1 shots ew. It is the biggest leak of all amongst rec punters. Even if they have an edge on the win part of the bet because they are a good judge they literally set fire to that edge (and more on top usually) by betting it ew and taking on maths which you just can't beat long term. As i have said before probably the best 100 ew bets i have ever had in my life i would say the vast majority of them have been shorter than 4/1 and 50% of them shorter than 6/4 and many decent odds on. Just think of Doob's bolded statement everytime you want to back that 16/1 shot ew because you always have or 'it is a good ew bet' blah blah. agreed,awesome post. i tend to look for non handicaps where the horse i'm backing at 10/1 will win that percentage of the time, but as the race is uncompetitive the place part is better,i.e under 2/1. the 5.30 at Tipp would be a good example betting All About Alfie at 9/1 (if i could) getting 9/5 on the place portion of the bet where the true odds are probably 6/4. @doubleup can't seem to get your calculator to work on iphone, is there another version for when i'm in the shops? Title: Re: Mathematics and Betting ThreadPost by: doubleup on May 14, 2015, 01:20:00 PM
@doubleup can't seem to get your calculator to work on iphone, is there another version for when i'm in the shops? ongoing project I'm trying to learn php to have the calculators run on the website rather than links from onedrive which don't work well on phones. Title: Re: Mathematics and Betting ThreadPost by: Doobs on May 14, 2015, 01:27:04 PM
First things first, I think betting a classic dirty each way using an online account is really stupid. By classic dirty each way race I mean one with an odds on favourite and a few rags. Firstly you often get mugged on the win price with the bookies, so you will find yourself taking 5/1 on an 8/1 chance on the machine. Secondly the very fact they are offering 5/1 on an 8/1 chance means that they are very aware that people are going to try and mug them on this race. The end result is that you will often lose your account and not even get much value on the bet that cost you it. Where you can make money and keep an account a bit longer is betting on good each way races. So what makes a good each way race mathematically? I am going to put togethether a couple of examples to show the difference between betting each way in a bad each way race and a good one. Race 1 is a good each way race, we have 17 runners and get quarter the first 4.We manage to find a runner that is 16/1 and bang on that price on Betfair. That means it has a 1 in 17 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 16/1 to finish in any position you choose in the race. So he is going to be 16/1 to finsh 5th, 12th or 17th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. As we know he has a 1/17 chance of coming in any position, we can estimate the odds he finishes in the first 4 places as 4/17. So if I was to offer you correct odds on the place as 13/4 or just over 3/1. Your average bookie will pay you 4/1. That is a near 18% uplift on the place terms from what they should offer you. If I could spend my life finding 16/1 chances in races like this that were 16/1 on the machine and had no horse picking skills at all I'd make 9% return on my money each time I make an each way bet like this in the long run. Race 2 is a bad each way race, we have 11 runners and get a fifth the first 3.Like race 1, we manage to find a runner that is 10/1 and bang on that price on Betfair. That means it has a 1 in 11 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 10/1 to finish in any position you choose in the race. So he is going to be 10/1 to finsh 3rd, 6th or 11th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. This should all be very familiar. As we know he has a 1/11 chance of coming in any position, we can estimate the odds he finishes in the first 3 places as 3/11. So if I was to offer you correct odds on the place as 8/3 or just under 3/1. Your average bookie will pay you 2/1. That is just over an 18% haircut on the place terms from what they should offer you. If I could spend my life finding 10/1 chances in races like this that were 10/1 on the machine and had no horse picking skills at all I'd lose 9% of money each time I make an each way bet in the long run. This is really crucial information to know if you are going to be putting a lot of each way bets on in the future. If you do find that 10/1 chance in that 11 runner race, you just have to stop backing it each way. Backing 10/1 chances each way is such an ingrained habit with punters that it might be hard to lose, but you should always look at the number of runners in the race before backing it each way. Each time that horse finishes 2nd and 3rd in that 11 runner race, 95% of punters will be kicking themselves saying they should have backed it each way. Many of your friends will happily point this out to you. You need to be one of the 5% who knows you absolutely shouldn't have and usually it isn't even close.Awesome post esp the bit about always backing 10/1 or 16/1 shots ew. It is the biggest leak of all amongst rec punters. Even if they have an edge on the win part of the bet because they are a good judge they literally set fire to that edge (and more on top usually) by betting it ew and taking on maths which you just can't beat long term. As i have said before probably the best 100 ew bets i have ever had in my life i would say the vast majority of them have been shorter than 4/1 and 50% of them shorter than 6/4 and many decent odds on. Just think of Doob's bolded statement everytime you want to back that 16/1 shot ew because you always have or 'it is a good ew bet' blah blah. agreed,awesome post. i tend to look for non handicaps where the horse i'm backing at 10/1 will win that percentage of the time, but as the race is uncompetitive the place part is better,i.e under 2/1. the 5.30 at Tipp would be a good example betting All About Alfie at 9/1 (if i could) getting 9/5 on the place portion of the bet where the true odds are probably 6/4. @doubleup can't seem to get your calculator to work on iphone, is there another version for when i'm in the shops? That is the type of race I avoid. It is close to classic dirty each way, and most of the bookies have ducked the 9/1 on the machine. Victor trader is new in the job obviously. There are reces where the maths will fall apart. You may see 10 runner group 1s with 3 or 4 horses that are rags, or you may get a short priced favourite in an 11 runner handicap. Most of the time you can just think good race/bad race before even opening Betfair. Title: Re: Mathematics and Betting ThreadPost by: peejaytwo on May 14, 2015, 01:41:50 PM
Quote As i have said before probably the best 100 ew bets i have ever had in my life i would say the vast majority of them have been shorter than 4/1 i agree with this as well but good luck trying to tell your average betting shop punter the merits of an ew double on two 2/1 shots. it seems ingrained in them that you can only bet ew if its 10/1 plus. just to complicate matters further.... what are your views on betting the imaginary 10/1 shot ew with a split stake. i.e 100 win at 10/1 40 place at quarter odds just to get the win stake back? its not something i do,but if i'm backing a horse for someone else he regularly does it and it winds me up no end. Title: Re: Mathematics and Betting ThreadPost by: arbboy on May 14, 2015, 01:56:15 PM
Quote As i have said before probably the best 100 ew bets i have ever had in my life i would say the vast majority of them have been shorter than 4/1 i agree with this as well but good luck trying to tell your average betting shop punter the merits of an ew double on two 2/1 shots. it seems ingrained in them that you can only bet ew if its 10/1 plus. just to complicate matters further.... what are your views on betting the imaginary 10/1 shot ew with a split stake. i.e 100 win at 10/1 40 place at quarter odds just to get the win stake back? its not something i do,but if i'm backing a horse for someone else he regularly does it and it winds me up no end. It is ingrained to them because the bookies PR men and media gurus bang on constantly about 'its a good ew bet' blah blah to sell you products that are profitable for them. When was the last time you heard a bookie pr man say 'this 4/5 fav in this 8 runner race is a cracking ew bet as the place is 1/16 on the machine and we are offering you 1/6! These pr guys quietly go about their business 'ingraining' this bullshit into the vast majority of punters heads because that is how they earn their salaries. Title: Re: Mathematics and Betting ThreadPost by: Doobs on May 14, 2015, 02:34:14 PM
There is always an exception.
The 4.20 at York is an 11 runner listed race, but has a really good shape (one short priced runner and 3 rags). Also Beteveryday are going quarter first 3, presumably as part of some York bettiing promotion. So Zuhoor Bayoona is 8/1, which is close to that price on the machine, but the 2/1 they give you on the place is quite a bit bigger. In addition, Profitable would be named well if they went 14/1. Title: Re: Mathematics and Betting ThreadPost by: Doobs on May 14, 2015, 06:19:26 PM
There is always an exception. The 4.20 at York is an 11 runner listed race, but has a really good shape (one short priced runner and 3 rags). Also Beteveryday are going quarter first 3, presumably as part of some York bettiing promotion. So Zuhoor Bayoona is 8/1, which is close to that price on the machine, but the 2/1 they give you on the place is quite a bit bigger. In addition, Profitable would be named well if they went 14/1. Profitable did indeed go 14-1 and live up to his name, not for me unfortunately. Title: Re: Mathematics and Betting ThreadPost by: sonour on May 14, 2015, 11:45:40 PM
Quote As i have said before probably the best 100 ew bets i have ever had in my life i would say the vast majority of them have been shorter than 4/1 i agree with this as well but good luck trying to tell your average betting shop punter the merits of an ew double on two 2/1 shots. it seems ingrained in them that you can only bet ew if its 10/1 plus. just to complicate matters further.... what are your views on betting the imaginary 10/1 shot ew with a split stake. i.e 100 win at 10/1 40 place at quarter odds just to get the win stake back? its not something i do,but if i'm backing a horse for someone else he regularly does it and it winds me up no end. It is ingrained to them because the bookies PR men and media gurus bang on constantly about 'its a good ew bet' blah blah to sell you products that are profitable for them. When was the last time you heard a bookie pr man say 'this 4/5 fav in this 8 runner race is a cracking ew bet as the place is 1/16 on the machine and we are offering you 1/6! These pr guys quietly go about their business 'ingraining' this bullshit into the vast majority of punters heads because that is how they earn their salaries. The manager at my local Corals laughs every time I bet short prices each way. He's not doing it for any clever reason, he genuinely doesn't understand. These are pretty much the only bets I can get on in this shop and they are probably my most profitable. :) Title: Re: Mathematics and Betting ThreadPost by: doubleup on May 15, 2015, 09:53:42 AM
@doubleup can't seem to get your calculator to work on iphone, is there another version for when i'm in the shops? ongoing project I'm trying to learn php to have the calculators run on the website rather than links from onedrive which don't work well on phones. formatting is a bit suspect but this should work on phones http://www.sportspreadsheet.com/eachwaycalc2.html Title: Re: Mathematics and Betting ThreadPost by: peejaytwo on May 15, 2015, 10:06:50 PM
First things first, I think betting a classic dirty each way using an online account is really stupid. By classic dirty each way race I mean one with an odds on favourite and a few rags. Firstly you often get mugged on the win price with the bookies, so you will find yourself taking 5/1 on an 8/1 chance on the machine. Secondly the very fact they are offering 5/1 on an 8/1 chance means that they are very aware that people are going to try and mug them on this race. The end result is that you will often lose your account and not even get much value on the bet that cost you it. Where you can make money and keep an account a bit longer is betting on good each way races. So what makes a good each way race mathematically? I am going to put togethether a couple of examples to show the difference between betting each way in a bad each way race and a good one. Race 1 is a good each way race, we have 17 runners and get quarter the first 4.We manage to find a runner that is 16/1 and bang on that price on Betfair. That means it has a 1 in 17 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 16/1 to finish in any position you choose in the race. So he is going to be 16/1 to finsh 5th, 12th or 17th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. As we know he has a 1/17 chance of coming in any position, we can estimate the odds he finishes in the first 4 places as 4/17. So if I was to offer you correct odds on the place as 13/4 or just over 3/1. Your average bookie will pay you 4/1. That is a near 18% uplift on the place terms from what they should offer you. If I could spend my life finding 16/1 chances in races like this that were 16/1 on the machine and had no horse picking skills at all I'd make 9% return on my money each time I make an each way bet like this in the long run. Race 2 is a bad each way race, we have 11 runners and get a fifth the first 3.Like race 1, we manage to find a runner that is 10/1 and bang on that price on Betfair. That means it has a 1 in 11 chance of winning. Just thinking about this situation for a bit you can realise that this horse is probably about 10/1 to finish in any position you choose in the race. So he is going to be 10/1 to finsh 3rd, 6th or 11th as well as first. It is never going to be exactly this but close enough for me to be happy I am making a decent asumption. This should all be very familiar. As we know he has a 1/11 chance of coming in any position, we can estimate the odds he finishes in the first 3 places as 3/11. So if I was to offer you correct odds on the place as 8/3 or just under 3/1. Your average bookie will pay you 2/1. That is just over an 18% haircut on the place terms from what they should offer you. If I could spend my life finding 10/1 chances in races like this that were 10/1 on the machine and had no horse picking skills at all I'd lose 9% of money each time I make an each way bet in the long run. This is really crucial information to know if you are going to be putting a lot of each way bets on in the future. If you do find that 10/1 chance in that 11 runner race, you just have to stop backing it each way. Backing 10/1 chances each way is such an ingrained habit with punters that it might be hard to lose, but you should always look at the number of runners in the race before backing it each way. Each time that horse finishes 2nd and 3rd in that 11 runner race, 95% of punters will be kicking themselves saying they should have backed it each way. Awesome post esp the bit about always backing 10/1 or 16/1 shots ew. It is the biggest leak of all amongst rec punters. Even if they have an edge on the win part of the bet because they are a good judge they literally set fire to that edge (and more on top usually) by betting it ew and taking on maths which you just can't beat long term. As i have said before probably the best 100 ew bets i have ever had in my life i would say the vast majority of them have been shorter than 4/1 and 50% of them shorter than 6/4 and many decent odds on. Just think of Doob's bolded statement everytime you want to back that 16/1 shot ew because you always have or 'it is a good ew bet' blah blah. agreed,awesome post. i tend to look for non handicaps where the horse i'm backing at 10/1 will win that percentage of the time, but as the race is uncompetitive the place part is better,i.e under 2/1. the 5.30 at Tipp would be a good example betting All About Alfie at 9/1 (if i could) getting 9/5 on the place portion of the bet where the true odds are probably 6/4. @doubleup can't seem to get your calculator to work on iphone, is there another version for when i'm in the shops? Title: Re: Mathematics and Betting ThreadPost by: peejaytwo on December 30, 2020, 11:03:16 AM
Took a little finding this thread, time flies.....
Anyway, things getting tougher on the High St, Baldy removing treble odds from L15s from 1/1/21. No rule change in my local Paddyshack yet but I'd be surprised if they carry on. |