Tuesday, 13 October 2009

Number crunching

By converting the odds of my 204 selections to their implied probability of winning; taking an average of those probabilities, and converting that average probability (12.35%) back into betting odds, I calculate that my average odds are 8.10. I'm doing slightly better than BSP which is 8.24.

The biggest factor in producing my current profit is that the horses I'm selecting lose more often than their prices suggest they should; 91.18% compared with 87.65%. That means seven horses have lost that could reasonably have been expected to win. So although I'm delighted to be ahead, these are relatively small numbers that I'm dealing with. If those seven horses win today, I'll be in the red.

The 91.18% strike rate is much higher than I had expected, and the £3.2 million question is WHY? Most likely it is down to the fact that 204 selections is too small a sample, and that the strike rate will gradually decrease. However there is another factor which has provided a higher strike rate compared with what the historical data led me to expect. When looking at the historical data, I only considered horses up to a maximum BSP of 16.0, which is my cut off point. My 204 selections include 45 with a BSP higher than 16.0, of which only 3 have won. Those 45 provide a strike rate of 93.33%.

I'm a bit wary of today's selections as they include two or three short priced ones, and I'm now expecting the high SR to be corrected. I'm also starting to think that my stakes liability is probably a bit too high at 4% of my bank. I'll leave it for now though.

1 comment:

JS said...

Interesting experiemnt Allan, will read on with interest as ever. Good luck mate!