OK here's one for you all.

I love reading the posts on this system part of the website, because systems are great. They're the promise of the pot of gold, the holy grail, the "discovery".

"EUREKA!" you cry as the set of results come in and it's in profit.

Then comes the dreams of sitting on a yacht, sipping champagne as you listen to your bets roll in, and of course the obligatory large mammoried blonde reclines next to you.

That is - of course - the illusion.

But I did read with interest the thread on the 4yo system recently, and it occurred to me, what's a good sample size for a system?

If for example you find a system that's winning 20% on turnover, then you're flying, but how reliable is that 20% for future forecasting? How many selections do you need in your sample size to be able to confidently say that the trend will continue?

Also, if the dividends of a system are calculated from SP, what improvement can one expect when using a variety of methods and choosing the best in the real world, ie products like maxi-div and best fluc and betfair and austote. If you're in front of your computer ten minutes before a race and you have all those at your disposal (though admittedly top fluc is not available ten minutes before), then surely you're going to average better odds than just SP.

Thoughts, peoples?

Undoubtedly the bigger the sample size the more confident you are of your results. My system which just covers WA is based on results from 1997 to present day and the fluctuation on a year to year basis is 97.2% returned for 1998 to 112.8% returned in 2002 (Based on Tabcorp prices).
This means if for example I had tried the system out at the end of 1998 I would have binned it as useless because it had a slight negative return - and that would have been based on over 3000 bets.
As my system chews through the data it updates the percent returned on screen after each race and the (rapidly moving figures) for each year shoot up and down wildly for the first part of a year, they can even move about quite a bit as the year being processed nears the finish. This just illustrates to me the clustering of wins and losses and convinces me that anything less than a couple of thousand results (unless you are showing a very significant win or loss percentage) is pretty meaningless. My system is based on form and selects a lot of favorites so I'm not talking about a system that is relying on a few long priced winners.
When I started using real money about a year ago, the first week I lost 7 out of 7 races but because I had over 7 years results behind me I never doubted it would come back to profit. The more data the more confidence you can bet with.

With regards SP versus other divvies. My system returns negative 0.8% on SP over the last 8 and a half years and positive 5.26% on Tabcorp. I don't know if that's typical or if my selections are just closer to bookies selections than Tab ones. On maxidiv which is where I bet at present I'm laughing. Nothing like hearing a horse pay $5.00 when you listen to the race on the radio and seeing you got 7 or 8 next time you fire up the computer.

KV

Thanks for that Kenny. Very informative.

The reason I put this post up is because I have been researching a bit of a system using my ratings, and over a roughly one year period there have been 320 selections, strike rate of 30%, ave div SP of $4.60 POT of 40%!

So, is 320 selections over about a year enough to get excited about?

It certainly is a promising beginning and I'd be feeling pretty good about it. But is'nt the answer to your ponder, how long is a piece of string.

As time goes by and your system continues to roll out profits consistently you must have confidence, but it could still show a negative, even it is just one year. Just sit down and hold on for the ride.

What else are you going to do?

Good Punting.

Yeah good point Top Rank. Your insight is, as usual, spot on.

For the record I thoguht I'd give it a crack today, looking at selections in advance for the first time. Today there were two, for one winner, paid $3.00, so I made a profit. If I replicated today's events exactly every single day I'd be a billionaire.

Hi Duritz
The first thing you should do is work out your "Difference between Win % S/R and the Win % S/R that will yield your Min Edge which is normally approx. 10%.
The formula for the above is Your Win%-(2+(2*Min Edge(.10)))/ avg payoff (to compute this avg payoff do the following (2*your avg payoff($3.60)+2.
based on your figures this should equate to 6.09%.

Now to find the minimum number of races computed to a confidence level of 99% do the following.
(your Win % * your Loss %)*(2.575/.0609)^2. the answer would be 376 races to provide you with a 99% confidence level.

Good Luck

Hi Duritz,
Pleased to see you've grasped the nettle at last. Or are you having a sly dig at sytemites?
First you say that systems are great, something of an about face from most of your previous threads, then you tell us we're dreaming or at least our prospects are illusory
And do you think that all systemites share the juvenile fantasy you have described? And if so, why only systemites? Do you equate us with the glossy brochures from the Gold Coast? I've never seen any posting from from you telling form analysts that they are chasing such pie in the sky.The inference being that you think more serious and dedicated form analysts have loftier ambitions maybe?.
Anyhow, be careful how you play with your systems. You just might get hooked.

p.s. If you need a hand with the champers or the blonde (while you're doing the form perhaps), I'm your man.

Fox don't get me wrong - I love systems. Always have. I love them because they offer fresh hope if you've had a losing day. You can go from being miserable as your get out in the last hides away in the back of the field to being ecstatic at about midnight that night as you are still up, swigging vodka straight from the bottle, wearing just boxer shorts and endlessly tweaking the rules.

I love systems because they are the promise of SOLVING IT, of BEATING it in one fell swoop.

I love systems for these reasons and always come back to inventing them because frankly it's fun, too. I love systems, I have just never actually believed they can win.

Doing the form is such a grinding way to win compared to them. Don't get me wrong, I love doing the form too. Tonight I thoroughly enjoyed doing full form for three races at Ballarat tomorrow which I will be value betting. I enjoyed the challenge and the thought process involved, but the yin to this yang is the system, where you don't have to think of the horses each as individuals and know what they can do and can't do.

I love the form when it works out, too. Like on Saturday I had been busy on Friday and wasn't that keen on Flemington anyway so just did Makybe Diva's race only, in Sydney. She was an absolute certainty for mine, and after I examined each runner with my weight ratings applied, it bore it out. Over 2400m, she was a certainty. Over 2000m, Grand Armee would've been a certainty. This is something a system could NOT have grasped, but of course the mind can.

I think overall I love systems because if you find one that wins it means you can have that most lovely thing - a daily punt - without having the endless grind of form. Trust me, you don't want to do the form every day. I love the form, but really try to restrict myself to just Wed and Sat (plus specials like public hols) so I don't burn out. When I do go and do too much form I get sloppy and end up LOSING on badly made bets. When I stay fresh I do the form RIGHT and I WIN because of it.

But I do like the daily punt, even if it's just a smaller bet on a couple of chances that a system throws up. That's why I try to find one.

As I said in another post, my grandfather used to keep piles of the Sporting Globe and would be endlessly going through them to try and find a winning system. He was no mug, either. In Phar Lap's Melb Cup he had $2000 pounds on the great horse at something like 8/11, won about 1550 pounds. Work that out to todays currency with inflation etc. He bought a mansion in Toorak from that.

But he never found the pot of gold sys. My old man has spent much of his life doing the same. I don't want to be that way. I do firmly believe that to have an edge long term you need to do the form properly and - VERY IMPORTANT - bet properly.

With that in mind I sort of expect this system I have invented to fall over. However, it has something going for it - it is based around my weight ratings. They are great ratings and are obviously not something anyone bar me (and my wife should she wish to use them, which she doesn't! and my 1yr old girl, who isn't yet saying "quinella" or "trifecta" but will) has access to, so that angle and edge may enable them to win.

At any rate, I am going to bet the selections it throws up, give them their chance. Mind you I won't be outlaying as much on them as I do on my value betting though. But, in time, should it continue, who knows.....

At the time of writing, the research I have done on them, using SP prices, comes up with these stats:

selections - 407
Winners - 129
s/r - 32%
collect - 620
profit - 213
%pot - 52%
ave win price - $4.80

As I said, that's on SP. So, over that time, even just say betting maxi div I think the POT would be higher.

Maybe it'll fall down. I'll find out because I'll give it the great test run - with the dollars down, the chips in.

G'Day Duritz,
I think I might have a clue for you as to why your systems keep falling over.

Maybe you should try Y-fronts, earlier in the day and whisky not vodka. And if that doesn't work I'm right out of ideas.

I must disagree with you about a system not being able to pick Makybe Diva to beat Grand Armee. Just off the top of my head how about in a 2400 race backing the horse that has won most money at 2400 or further? I guarantee that using that simple plan MD would have been an even bigger cert than on your weight ratings.

Anyway, I have another system that needs some attention so I'm off to find a bottle and change my daks.
Happy punting.

How about shortest priced or highest rated horse that had been placed at the distance of today's race. Or any horse placed at today's distance which had won it's last start exactly 7 days ago.