Newby - System Sample Size question...
 

Which (theoretical) bet to place system is best?

System One
$10k bank
$1k bets (10% takeout)
Races 990
Wins (PLC) 746
Strike Rate 75.4%
Avg Win Div $1.40
Profit on Turnover 5.21%
Profit $51,540
Max bank risk 36.9%
Avg bank risk 15.4%
Max outs 5


System Two
$10k bank
$1k bets (10% takeout)
Races 688
Wins (PLC) 520
Strike Rate 75.6%
Avg Win Div $1.40
Profit on Turnover 6.84%
Profit $47,080
Max bank risk 39.8%
Avg bank risk 14.6%
Max outs 6

Profit and bank risks are broadly similar...

Is the 30% larger sample size in System One significant enough in terms of improving predictability / reliability to justify the “cost / benefit” associated with a slightly lower POT and having to place an extra 300 x $1000 bets for an additional (approx) $4k return???

Thanks in advance for any helpful comments...



p.s. above bet numbers are based on placing 2 to 3 bets / week.

Mmmm, these are always tricky.

Bet em both!

Have a look at this calculator here, handy wee tool that someone much smarter than me recommends for testing confidence in system testing.

http://statpages.info/confint.html

Using the numbers from your above stats in the binomial confidence calculator, I would be reasonably confident to start to bet both of them provided you are pretty sure you are not going to affect divis.

Expected variance of SR for the systems

System 1- 72.55 - 78.01%
System 2 - 72.19 to 78.75%

Using the lowest SR there you still end with a positive ROI, 1.066% POT.

Thanks Thorns

http://statpages.info/confint.html is an awesome resource - appreciated.

Hi Sample,

Your results are looking similar to what I am trying to achieve in a simple selection process I started 11 weeks ago, only on Saturdays. Only about 3 to 4 bets per Saturday. Only takes 5 minutes to work the bets out. Very early days yet but running at 54% Win and 90% Place. I haven't done any back testing on it.

I am having 4 equal bets per selection. Win Top Fluc,.....Place,........Running All Up Double for the Place,,....and Running All Up Treble for the Place.

A site like CrownBet is good as you get the Best of the 3 Tabs, for both Win and Place Divs.

I'll study that link later on when I get some more time.

Regards, Paul

Your serious on this ? 1K bets on a 10K bank. I'll assume your joking on that part and your more likely to bet $100 per 10K which is still stupidly high.

You really don't have enough information (or have not provided the right information) to make a judgement call on either system. Right now I would say both would be thrown away as far I was concerned. I have thrown away better systems then the two you posted. You may ask why ....

1. You haven't taken into account the affect of your bets on the market. It looks like you are betting the place for those strike rates. Your $1K bet will turn many of your $1.40 into $1.30 on the tote. If you try to bet those successfully with a bookie good luck getting 1K on. There isn't enough cash in the betfair place markets to handle those bet sizes without significant issues in changing the Betfair SP price to a losing price.

2. Your overcommitting if you think you can bet 10%. 1% is crazy enough. I don't even bet close to 1% and have a much higher strike rate then you.

3. Max run of outs is a laughable statistical measure. Sure use it as a guide but its basically of little use unless you multiply it by at least 3. The problem is it doesn't take into account losing 5 times then winning once and then losing 4 times. You now have lost 9 out of 10 bets and your bank is at 10%.

4. If you really think you can handle losing say 30% of your bank and not have heart palpitations and extreme stress levels then you truly are a gambler at heart. Try for a maximum of 2%-3% of your bank instead as your maximum drawdown.

5. You need to provide much more information. How long is this tested across ? I am assuming years based on 2-3 bets per week ? How many of those periods were up/down. Is at least every year in profit ?

There are at least another 4 things I would consider before even contemplating even looking at improving one of these systems.

The problem most system punters have is they don't understand the numbers inside out. Can you tell me the distribution of losers over 10 bets, 100 bets , 1000 bets ? Can you tell me the likely recovery period for a loss? Can you tell me the expectation of your losers tomorrow based on today ? Can you tell me whether your results are based on luck or an edge ? Can you tell me why your systems have an edge. What gives you that edge that the other punters don't know. By the way I want you to ask these questions to yourself not actually just tell me the answers as I don't care what they are but you should.

Challenge yourself to do better. These are mediocre systems at best which could be used by an amateur punter with a small outlay. You don't need to listen to me but I do know what I am talking about when it comes to systems as in the last 30 months of punting(2.5 years) I have only had 2 losing months which both only produced a small loss. Both were due to me being overconfident and greedy and not sticking to my hard rules on what classifies as a successful system.

Thanks very much for the helpful comments and advice about my aforementioned "theoretical" system... very much appreciated.

In terms of the real world, the idea of risking $300k to potentially profit an additional $4k and obtain the security of a marginally larger sample is probably nonsensical - vis-a-vis "theoretical system".

Best and thanks


:)

Systemsamplesize, my 2 cents worth, I am a place bettor from way back, still using the same method of selection though there have been a few tweaks over the years.

I've been using $100 bets for many years, though I have a lot of bets over the course of a week. A few years ago I decided that my method was good enough to increase stakes, I had $1000 bets in mind possibly spread over several bookies/ corp orates etc. but decided to cautiously increase in $100 increments.

I can't quite remember at what stage my usual 4% POT was shrinking, but certainly before I reached $500 bets; it had disappeared. I reverted back to $100 bets and presto it slowly hovered around the 4% POT again.

Now I bet most days, I noticed that there seemed to less effect on Saturdays and possibly Wednesdays, but on other days there was a definite effect on the Divvies.