Hi Lomaca,

Didnt want to take over the other thread so started a new one,i hope others will post their opinions aswell but this is mine.


Its all about the profit on turnover.

Im trying to target races that have a greater chance of producing a result where the available dividends are much larger than the true odds of my selections.

Its my expeirence that this happens far more in larger fields,its all about the cut off point,it can change depending on the type of bet.

The situation i listed with my top 2 providing the quinella at $195 for a $1 outlay and the top 3 filling the trifecta at $3009 for a $6 outlay might
not happen very often but at 195 to 1 and 501 to 1 they were both massive overlays compared to the true chance of them finishing in that order,in a smaller
field the chances of this kind of massive overlay just doesnt exsist.


Here's an example of the benefits of filtering to field size from a system im currently testing-

All races =
714 bets-201 wins -$700.40 return - 0.019% loss on turnover

Races with 7 starters or less =
104 bets - 33 wins -$72.40 return - 0.303% loss on turnover

Races with 8 starters or more =
610 bets - 168 wins - $628 return -0.029% profit on turnover


* so weve taken a losing system and turned it into a profitable one by simply ignoring races with less than 8 starters.

This is from well fancied horses,the situation is exagerated even more with longer priced horses.

Cheers

Thanks for that Dale, let's see what others think of this.

I personally never considered field sizes seriously, mainly because my rating seems to work OK in any field size, and for an other, I do not bet multiples at all.

Good luck

Dale,

Very insightful post. Lets back that up with some more tests. I'll use tote figures only.

Rule 1 : Top unitab selection

Field size < 8 had 910 selections for a return of 729.6 = 20% lot
Field size 8-12 had 5911 for a return of 4975 = 16% lot
Fieldsize > 12 had 7627 for a return of 6510 = 14% lot.

As you predicted removing smaller fields produce a less loss or greater profit.

The reason I believe this the case is that the extra horses are generally no hopers anyway, but by having extra horses their is extra risk thus increasing the horses odds by more then the actual added risk.

Thats it exactly,the increased odds are greater than the added risk.

Funny. I bet to IAS prices using Market Forces and guess what the 12 horse plus fields through up overlays on the superprice like you wouldn't believe. This I believe is something I've caught onto since a few weeks ago and the strike rate of the top 2,3,4 favourite still works out the same as smaller fields!

So from now on I am only going to bet on races with a min of 12 plus starters after scratchings. Most runners are just fillers as mentioned below.