Two For The Price Of One

[stat man]

The exchange odds, of a horse, at the off, are, for all intents and purposes, perfect. Therefore, the strike rate of a horse is proportional to its exchange odds at the off. For example, if its odds at the off are 4.0, then its strike rate will be approximately 25%. Now let’s take a set of horses. The set contains all 2^nd favourites in all races. What do we know about this set before we even start collecting data? Firstly, we know that the strike rate will be proportional to the average of the 2^nd favourites’ exchange odds at the off. Secondly, we also know that this set will approximately break even, ignoring commission and the bookmaker’s overround, regardless of whether we back or lay all 2^nd favourites. Now let’s suppose that we devise a theory that clear 2^nd favourites whose odds increase during the last 60 mins. of betting have a higher probability of losing than their odds imply and should therefore be layed to lose. Let’s suppose that we collect data for 2^nd favourites whose odds increase during the last 60 mins. of betting and find that the ROI, after commission, when the selections are LAYED to lose, is 11.5%. What else do we know? We know that the ROI of 2^nd favourites whose odds don’t increase during the last 60 mins. of betting, when BACKED to win, MUST also have a ROI of 11.5%. Although we SHOULD really test this out, we don’t really NEED to because Set Theory dictates that this must be true. Therefore, whenever we devise a system, we actually devise a second system automatically. The second system is always the complimentary of the first system. The theory can be expressed mathematically as follows. S = 0 Where S is a set that has a ROI of 0. If S1 and S2 are subsets of set S, then S1 + S2 = 0 therefore S1 = - S2. If S1 makes a profit as a backing system, then S2 must make an equivalent loss as a backing system. If S2 makes a loss as a backing system, it must make a profit of equal magnitude as a laying system. Using the above example, S is all 2^nd favourites. S1 is those 2^nd favourites whose odds increase during the last 60 mins. of betting. S2 is those 2^nd favourites whose odds do not increase during the last 60 mins. of betting and is the complimentary system of S1. Now, the above is merely an example. I really have no idea whether or not laying 2^nd favourites whose odds increase during the last 60 mins of betting produces a profit. However, if it does, you can be sure that backing those that don’t will also produce an equivalent profit. I’m sure that you can come up with similar sets of horses and similar theories. The beauty of using this theory is that you get two systems for the price of 1 (a backing system and a laying system). Provided that one is profitable, so must the other. Bottom line: If you can create a system that makes a profit as a laying system, a complimentary system must also exist that makes a backing profit and vice versa.

[The Saint]

Re: Two For The Price Of One

The exchange odds, of a horse, at the off, are, for all intents and purposes, perfect. Therefore, the strike rate of a horse is proportional to its exchange odds at the off. For example, if its odds at the off are 4.0, then its strike rate will be approximately 25%.

The perfect description of why 'beating the book' is so important and getting on above Betfair SP is the most crucial factor to the profitable punter.

Bottom line: If you can create a system that makes a profit as a laying system, a complimentary system must also exist that makes a backing profit and vice versa.

You would think so wouldn't you....! :lol ;) To be fair, I am 100% sure that you are right - as soon as I stop laying AW 'plots' that subseqently hack up!!! I have - finally - but as you identify/suggest above using the market in conjunction with what one thinks they might know is so, so crucial to both backing and laying success. The attitude of assuming all protagonists are 'at it' until proven otherwise serves very well on the Sand imho.