Hi
I have created a spreadsheet using Sporting Indexs Total Goals and Supremacy markets and applies 'Poisson' to them to determine 'true prices' for various markets.
I am looking to adapt this model to InPlay but need help with the following:
 Once a goal has been scored, I can not simply input the new quotes offered by Sporting Index as my model will still return a value for impossible scores. I need to erradicate this whilst still keeping my prices to 100% and I am unsure of how to encorporate this.
Any help appreciated.
Also, another question, what sort of percentage should I be looking at for draw inflation?
Thanks
I assume that you have made a matrix to calculate the probabilities of different scorelines and are working in Excel.
After a goal has been scored, I would suggest making the probability of impossible scorelines 0. This will make the total probability <1, whereas it should =1.
Next, make another matrix, adjacent to the one you're working on and link the respective scorelines from your original matrix to your new matrix.
Then, in the new matrix, divide the value of the scoreline probability by the total probability from your original matrix, which should be <1.
When the totals of all the scoreline probabilities in the new matrix are added together, they will =1.
Try the diagonally inflated model ... Link
Last edited by doubleback; 25th November 2012 at 07:08 PM.
Your link is excellent, however, I think a thorough understanding of the material contained here will lead to a far easier understanding of the complexities mentioned there.
http://en.wikipedia.org/wiki/Poisson_distribution
This should make things easier for those who did not study matrices in their youth.
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Drifter (27th November 2012)

Thanks Custard, that really simplifies it.
No problem ! I can still remember feeling angry that I had to learn all about matrices when I would have no practical use for them. I had to do mathematics as a first year subject in my Chemistry degree course but, of course, that was many years ago. What possible use could there be for matrices in a steelworks ?
I'm sure you can easily imagine how glad I am now that I was made to study them. I don't know how I could manage without them these days.
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PC0845 (25th November 2012)

There is not a straight forward answer, I'm afraid. When I found that paper I had the same thoughts as you. With gritted teeth, I diligently went through the paper educating myself along the way, armed with the mantra 'nothing is unknowable'. After months of devoted concentration, I attained full comprehension. Alas, it's not something I am going to share lightly. I could give a full explanation, but that would take the fun out of it. Go on a journey, my son, use perseverance and enlightenment will surely come.
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lcredd (27th November 2012)

I agree. It's something which one has to do for oneself, not just for the added knowledge it provides, but for the warm feeling one gets knowing that the model is as good as it could be. Even more, just look at the money you save by not having to pay strangers for this sort of information. Make your own model and if works you will be chuffed !
It's thanks, in part, to my model that I didn't back the Over 2.5 goals markets in today's televised games. It didn't tell me that both games would be 0  0 but it was clear that there would few goals. I never back Unders but I saved losing on Overs.
Interesting topic. Something I always wanted to look at but haven't yet. With the lack of Horse Racing in the winter this is something I can look at for the future.
I agree that coming up with your own strategy/model will be more satisfying and hopefully more profitable. I just hope I can find one.
I'm more than satisfied with this one
Another, so called 'lady', that wears a wig ...
Wigs ? You've lost me.
It was a reference to your penchant for ladyboys, who may wear a wig, and Naomi's battle with baldness along with her masculine temperament!
I have seen thousands of ladyboys and am certain that none has worn a wig. Only female impersonators, like Danny La Rue wear them. We knew an entertainer in Thailand who impersonated Shirley Bassey and Tina Turner and he wore wigs. He was totally straight, super fit like a kick boxer, and it was impossible to recognise him out of his stage costumes.
No penchant on my part just a totally open mind.
Getting back on topic (well, sort of), Ihave another question;
I have produced a model the predicts every teams points at the end of the season, how I arrive at this figure isn't important. However it needs a little tweaking, the way it works is by predicting what % of their future available points a team will acheive and adds this to the teams current points total. At the moment if you add up all the teams points it totals more points than are achievable over a season, it isn't a million miles out but I'd like to get it as realistic as possible. What sort of reduction factor could I apply?
Would it be something like find the maximum points available, divide my total points by this and then multiply teams points by this figure?
I guess alot depends on what you want to do with the predicted points, are you betting on the spreads or just trying to form your own league table for relative positions of teams within the league. It's never going to add up perfectly because your figures are based on probabilities rather than having your table worked out by predicted results.
Here is a new link to the same thing ...
http://scholar.google.co.uk/scholar_...=0CB8QgAMoADAA
dude67 who posts here created a nifty calculator which includes standard Poisson, bivariate Poisson and bivariate Poisson with diagonal inflation with a choice of either a Geometric distribution or a Bernoulli function.
http://www.thebetpro.com/calculator/
www.thebetpro.com is not working
Try sending a message on here to dude67 to ask wtf is going on!