The flaw

The flaw is that the historical results have the benefit of being able to look into the future; a powerful tool if you are trying to predict horse races!

That's why the system is at its best when the day is higher than the month. On 12th January 2009, the program looks for each horse's previous runs in races before 12/01/2009, but it receives their runs prior to 01/12/2009, including the races on 12th January!.

I've been very lucky for two reasons. I made nearly £1000 on an unprofitable system over 6 weeks with more than 1000 bets. I was also lucky to have spotted the bug on one of the days where it had any effect.

So I've gone back to the drawing board, and I think the basis of my system is still good, but nowhere near as profitable as I had previously led myself to believe.

The analysis

I've now had a chance to analyse the effect of the bug.

Firstly, in deciding whether or not a horse is a selection, the program looks at all of the previous races relating to that horse. The bug is due to the default method that dates are handled. I ask it for all of the races before 07/11/2009, and instead of giving me the races before 7th November, it gives me the races before 11th July. It expects the American date format. However, it handles most dates correctly. It knows that 23/09/2009 has to be 23rd September, because there isn't a 23rd month.

The bug only effects 11 days every month; the days before the 13th, but not the day that is equal to the month. From the 13th onwards, the system is a loss maker. For those 11 days each month, the system (with the bug) is hugely profitable. Then I noticed something even more exciting; there is a large number of selections that are made by the system WITH the bug as well as the system WITHOUT the bug. By removing the bugless selections, the system is even more profitable.

That's not all though, I discovered that if I removed the selections that are made on days where the month is higher than the day, the system becomes even more profitable, because the others make a loss. So it makes big profits on 12th January, and big losses on 1st December.

I had discovered, by pure chance, the perfect system. I'd only have to place bets on about 70 days a year, and have fewer selections to lay on those days. I'd also be fantastically rich, and that would be useful as I would spend the second half of every month in a different sunny country, where I'd have my own apartment.

Then I spotted a flaw in my plan. Maybe you have too?

Oh dear!

The system is now on hold, and may even be finished.

I spotted that the selections made from historical data were not exactly the same as those being selected each day. It turns out that there was a bug in the program that makes the selections from historical data. I've fixed the bug, and it now shows the system to be a loss maker.

This is very disappointing, as well as embarrassing! All may not be lost though. I need to compare the selections from the buggy code with the selections from the debugged code, and try to work out how different they are. It sounds daft, but it's possible that I may end up adding the bug to the code that makes the daily selections.

Still, I've made almost £1000 in six weeks, so it's not all bad.

Will post again once I've analysed the data. Hopefully I'll be able to salvage something from it.

Day 42

Win Lay System - Day 42
Today's starting bank: 3382.28
Today's profit: -418.47
Profit since 28/09/2009: 963.81
New bank: 2963.81
New stake liability: 74.10



The target graph now incorporates Maria's Laying System results in yellow. My lay results in blue and target in red.

Day 41

Win Lay System - Day 41
Today's starting bank: 3849.15
Today's profit: -466.87 (corrected)
Profit since 28/09/2009: 1382.28
New bank: 3382.28
New stake liability: 84.56

Another worst day!

I suppose if the system is going to behave the way that the historical records suggest, then I should be having worst and best days regularly. Worst days are harder to take though because, while I'm living it, those days make me doubt if it is really going to work at all.

I take some comfort in having reduced my liability level to 2.5% of bank.

Saturday preview

Of today's 638 declared runners, I'll be laying 410.

At least they can't all win!

Day 40

Win Lay System - Day 40
Today's starting bank: 3108.38
Today's profit: 740.77
Profit since 28/09/2009: 1849.15
New bank: 3849.15
New stake liability: 96.23

I had my worst day earlier this week, and now my best. :0

Despite today's most welcome profits, I'm dropping the daily liability to 2.5% of bank. I feel I need to reduce the risk of going bust because a lot can happen in a day. When I automate the bet placement, I'll try to recalculate my bank and stake liability before each race.