I have been working on a system for laying horses and need some advice.

My database has provided the following approximate infomation when backing the selections for a win over the last year (every raceday):-

2000 selections
17 % strike rate
31% Loss on Turnover.

My thinking is that this would make a good laying system.

Any advice on what further testing I should complete.

Brad

i may be a cabshazed minda but i can see that if you wish to lay you have to be at the screen and get the lowest price ...i always thought i couldnt pick a winnerr to save my miserable life then along came betfair....bollocks picking a loser is harder by a long shot dont doit """ laying is for chickens''

I intend to use one of the Betfair Automation Tools to place bets just before racetime with some price parameters.

Bradw

What's the average and median SP's for all selections, all winners and all losers?

__________________
Pixie

"It's worth remembering that profit isn't profit until it's spent off the racecourse." -- Crash

All - Average - $8.97 Median - $5.70

Winners - Average $4.00 Median - $3.40

Losers - Average $9.97 Median - $6.50


BradW

Bradw

On the figures supplied I think you'd have a negative expectation of about 6.5%. We should really be using the sum of the chances of all selections, not their average SP, but this is close enough.

Observed successful lay selections =

Total Lays * (1-Win SR) = 2000*(1-.17) = 1660

Expected successful lay selections =

Total Lays * 1-(1/Average SP all selections) = 2000*1-(1/8.97) = 1777

Advantage = (1660/1777)-1 = -0.0658

What this is telling us is that you should have had 117 more successful lay bets than the 1660 observed based on the average SP of all your selections. So in the long term you could expect to lose $0.0658 for every lay doller risked. You need to find a way of getting your lay strike rate up without increasing the average SP of all selections, or try to reduce the average SP of all selections whilst maintaining your strike rate.

Please somebody else check this as it's getting late and I've had a crap week.

__________________
Pixie

"It's worth remembering that profit isn't profit until it's spent off the racecourse." -- Crash