- This topic has 46 replies, 15 voices, and was last updated 17 years, 9 months ago by
.
-
Posts
-
I disagree with the contention that you must beat SP to achieve value- this seems to suggest that the SPs equate to the real odds of winning, or that the SP market is 100% efficient, patently not true.
More wise words.
It has always struck me as a particularly tasty paradox that people with a certain approach rely on the efficiency of the market on the one hand (favourites, second favourites, the whole damn systems kaboodle in particular) when betting’s very purpose is to exploit flaws in the market (or resign yourself to having "fun" bets).
Artemis,
The example given used 100 trials for simplicity. The argument and answer is much the same if you chose 1000 trials. 100 trials in the band of getting 10/1 about a horse you believe to be 8/1 takes an awful long time to happen. I never mentioned the long run. As an optimist I don’t accept the concept of ever being dead or broke. ;)
Carvillshill,
I understood what you said about the long term. Getting value is nothing to do with the long term. My argument tried to disprove your assumption. Each and every race in the simple example provided got value by backing a 8/1 horse at 10/1. Whether you win or lose after a series of races using that criteria is down to chance. The bigger the margin the better the chance of profit, (as per RobNorth earlier post), but the margins are generally very small in practice.
I would not wish golf on anyone, but selection method comes first – the bet follows only if you can get a good price. If your strike rate is 33% then it is no good backing value bets if they average less than 2/1, for example. I did not state you must beat SP to achieve value. I said this was a simple test of whether you are getting value.
SP, in the lower ranges, is proven year after year to be just below the expected strike rate for the long term case. The SP market is efficient, on average, over a year, but in any single race it can have individual horses too short or too long. Again, I did not suggest SP was a "true odds" price. Inverted commas were used throughout.<br>That is why you need to have your own better estimate of a "true price" odds-line before the markets opens. Of course you make the bet when the price offered exceeds your "true price" estimate. This is the whole point of having the "true price" established in the first place.
Robert
<br>
I suppose where we differ on this is that I contend that if your edge is small enough to be affected by chance over a decent interval of time (ie to make the difference between winning and losing) then it is too small to be worthwhile.I therefore feel that profitability over time is a worthwhile measure of whether value is being obtained.<br>I agree in principle with the idea of making an odds line, but must admit to seldom doing it: In practice I go by the percentage of the betting I can eliminate with confidence to see if I am likely to be able to get value, say being against a 2/1 fav when they bet to 108% would in theory mean the selection has a good chance of offering value.
BTW how can you possibly say the SP market is efficient over a year? The only way it could be efficient is if on average 10/1 shots won once in 11 tries, 2/1 pokes won 33% of the time and so on.(less overround if you like)This is so obviously not the case over one race or one year that to say it is an efficient market is ridiculous.
Carvillshill,
I think you are missing many of the finer points here. Perhaps you have little knowledge of the basics of probability.<br>You are making fundamental and contradictory errors in your assumptions.<br>Edge is not effected by chance (random events). It is the difference between calculated "true" chance and the price (expressed as a probability) you can obtain, .<br>For value to almost guarantee a profit long term then you would need regularly to get say, 10/1 about a true 6/1 chance or less. This is a rare event in a competitive market and your practical edge would be far less if you have more than a few highly selective bets a month.
If the favourite is a totally false one then you have a far better (but not automatic) chance of getting value within the rest of the field. You still have to know which alternative one is providing the value to be sure – so you still need an odds-line as a reference point. You also need to be sure of how false the favourite actually is.
If you inspect the figures for price bands and winning percents over a year you will see that what has been said is correct. It is obvious that you are ignorant of such data and its huge relevance to basic betting strategy.<br>You also have difficulty comprehending what was clearly said. I stated that in any particular race you can have horses too short or too long. Over a long period these errors (up and down) average out so that the average is almost the same as the odds expressed as a percentage in the lower odds range. Over-round per horse and the short pricing of long odds horse makes the small differences in the annual figures.
Robert
Robert99,
Carvills may be missing some of the finer points of this argument but you are obviously not. Would you care to post a few of your odds lines here so we can all benefit from your brilliant insights?
I’d love to get into this again but I’m off on hols- like the governor, I’ll be back!<br>I’m always suspicious of people who are difficult to understand, though….true intelligent insight is usually simply expressed, I find!
ACR1,
The discussion point is about the belief that a profit is an irrefutable proof about having obtained value. The examples I gave are about as Homer Simpson simple as you can get – the practical reality of reliably obtaining value is far more complex – which is possibly why it proves so difficult for many to make it work – I don’t make the rules or make the markets. No brilliant insights have been revealed ( I hope) – no complex mathematics used – no obtuse probability concepts – just a small part of the basics of betting. If you want to learn more on odds-lines theory and practice then join a forum such as SmartSig where this issue has been thoroughly discussed and before-race examples regularly given, as well as "free" software made available to do your own lines.
Robert
Robert<br>Firstly let me say how annoying it is to have a discussion with someone as obtuse as yourself- you are the most arrogant correspondent on this forum by a distance, as your every sentence says that you are right and are merely humouring the rest of us mortals: get a little humility into your life, you might even change your opinion on something to your advantage.<br>I have as good an understanding of probability as the next man, and at no time did I claim that edge was affected by chance. What I said was that over a sufficient sample size if one has an edge useful enough to be profitable ( Which would indeed be greater than getting 10/1 about true 6/1 chances) then profit is not chance-dependent: If a punter wins year in year out he unquestionably has an edge, and is unquestionably getting value, perhaps not on every bet but overall.<br>The random variation in actual winners obviously affects profits over weeks or months but if the method is sound profit over larger sample sizes and longer periods is assured. If you give me 11/10 against heads I may lose to you for a while but you will eventually go broke.<br>I am willing to bet that many sucessful punters on this forum and elsewhere don’t make odds lines for all the events that they bet on. It is for me sufficient to have an opinion based on previously successful methods that a certain price is wrong to make a bet. Your method may be more methodical, requiring you to price every horse in every possible betting event- that doesn’t make me wrong or ignorant of probability or otherwise less of a God than yourself, just different.
Value opposing Kandidate in the first at Lingfield today 1/2 fav never having run on sand nor winning a race.
Not Value backing an evens or below runner in a handicap.
Value getting the best price you can.
Not value getting the worst value you can.
Value winning
Not value losing
Value making a profit overall
Not value making a loss
Hope that clears it up.
:laugh: @ Dungheap
I think people get too caught up on the whole concept of value and start getting awfully wound up about %ages and irrelevances. They seem to forget for any that to mean anything you have to be backing winners.
Measuring value when betting is difficult but possible to achieve in limited fashion by applying a simple arithmetical calculation to any rating figures.<br>Taking the next race at Hexham today, Feb 5, 07 and calculating the fractional odds from the percentages derived from RPR and Adrian Massey the outcome is:
2.30 Hexham<br>Thatlldoforme = RPR’s opinion 9/4, Massey 3/1 (SP 11/4)<br>San Peire = RPR 11/4, Massey 95/40 (SP 7/2)<br>Open De L’Isle = RPR 9/2, Massey 7/2 (SP 2/1)<br>Not perfect but it does provide independent advice to compare with market offers.
(Edited by Formath at 5:51 pm on Feb. 5, 2007)
- You must be logged in to reply to this topic.