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Michael Wilding
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20/01/2020 10:51 am  

Congratulations @bfrew7, a lot of hard work and time went into this, and you've got something working well. Stick with it as it is, and you'll be amazed how a solid approach needs very little adjustment once you have it.

It would be a good idea now you have the data, to calculate some expected downswing timeframes, this will ready you for what to expect before it happens and helps to prevent you going on tilt when it does.

I'll look forward to the weekly updates, and if you have time another thread trialling a new approach 🙂


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AndrewP
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20/01/2020 12:15 pm  

Well done Brian.

I've made some corrections to the sheet.

https://www.dropbox.com/s/wx1v947mksxmoif/Andrew%20P%27s%20BF-DutchSaver-Record-Sheet%20till%2019-Jan-20%20%281%29.xlsx?dl=0

1. Formulas put back in cells N56, N97 & N101 as they had values entered in them. Cells with formulas in are now protected.

2. Corrected the way net profit is calculated in the 'stake each selection to return 1 unit' section (cell U5). Keep an eye on this, it is telling you what percentage profit on turnover you would have made had you backed each selection to return 1 unit. One unit could be any fraction of your original bank, whatever you feel would be 'safe' given the strike rate.

3. Added some additional information so you can see the bank growth with 'stake each selection to return 1 unit' depending on how many units of bank you enter in cell Y1. Again, it is whatever you feel is 'safe'.

4. Added the Chi2 figure to the sheet in cell Q6. Keep an eye on this over the next 100 races and see which way the trend is. Ideally, it will drop below 5% and stay there.

5. Entered figure in L300.


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Brian Frew
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20/01/2020 5:22 pm  

Many thanks Micheal and Andrew P.  The help with this from both of you is much appreciated.  

Michael, I am very aware of the downswing possibilities and that is why I am only increasing my stakes very steadily.  I am looking to have at least 6 times my standard stake (currently £40) in profit before I consider increasing it - with 6 being the largest expected negative run at a 70% strike rate.  If I was in the middle of such a run, I would start reducing my base stake after 3 X current stakes of losses (i.e. £120 down at the current stakes).  Does that plan sound reasonable?  

Andrew, those additional tweaks to the spreadsheet are very welcome and will definitely help me monitor progress.  By the way, I am two thirds of the way through "Fortune's Formula" at the moment and enjoying it.  Some of it I was fairly familiar with (particularly the Blackjack stuff) but other parts like the connection to Black / Scholes is new to me.

I have started looking at a tweaked version of Michael's webinar place approach.  I'll post on it when I am reasonably confident that I have something worth folk looking at.


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AndrewP
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20/01/2020 10:48 pm  

I am looking to have at least 6 times my standard stake (currently £40) in profit before I consider increasing it - with 6 being the largest expected negative run at a 70% strike rate. If I was in the middle of such a run, I would start reducing my base stake after 3 X current stakes of losses (i.e. £120 down at the current stakes). Does that plan sound reasonable?

I would be very cautious about increasing stakes until you have a lot more data Brian. My simulation of 10,000 x 1,000 bet sequences with a 1% advantage produced a losing run of 10. However, it's the multiple shorter sequences punctuated by short winning runs that you have to watch out for. My simulation produced a maximum drawdown of -119. It's a cruel fact of statistics that the longer you play the more likely you are to hit long losing runs whilst still maintaining a strike rate of 70% ish (Bernouli and the law of large numbers).

When you've finished Fortune's Formula perhaps I'll start a thread on bet sizing, the dangers of over-staking and why you should bet a percentage of bank relative to odds (and conservative advantage). In the meantime, I've attached a table of optimum bet sizes relative to odds and edge. Note the odds and advantage at which 1% of bank occurs (where the colours change). Most people over-stake, often as high as 10% of bank and wonder why their bank balance is so volatile and keeps coming back to where it started.


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Michael Wilding
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21/01/2020 2:28 pm  

I agree with what Andrew said about the downswings vs losing runs. It's the losing sequences broken by short winning runs that are the bankroll killers, and it's them that you need to account for.

I wouldn't increase stakes so aggressively, but there are other things to take into account in staking. 

The way Andrew suggests is the best for long-term bankroll growth, without any doubt. Based on Kelly, I would personally go higher than a 1% edge based on current results, probably somewhere from 3%-5%, but over-betting Kelly is the quickest way to losing your bankroll. Thank you for sharing that spreadsheet @andrewp it's superb.

However, not everybody is after bankroll growth. If you can, and are happy to, replace your bankroll if you lose it, then you may be happier with a higher stake than may otherwise be recommended if it's a hobby and something you purely are looking for enjoyment from.

If you're after a long-term bankroll growth and income, then you want to be following what Andrew has already suggested which is the best way.

Of course there's in-between those two as well. Deciding what you're after long-term from your betting is the key decision maker here.

Personally I look for the long-term bankroll growth and income, so I do pretty much exactly what Andrew has suggested. But at Festivals I have a "fun" bankroll which I use to bet completely differently for the enjoyment of watching the sport.


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Michael Wilding
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21/01/2020 2:29 pm  

@andrewp would be great to see a thread on bet sizing.

On a different note, would it be useful if I put a thread in the forum for shared files, such as the Kelly one above, which can be easily found for anybody to use?


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Alex Bradley
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21/01/2020 2:54 pm  

@admin

Yes it would be useful with explanations as well 🤓 


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Tony Mochrie
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21/01/2020 3:06 pm  

If I remember correctly the maximum number of losing bets in a sequence increases as the number bet bets increase, even keeping the same strike rate. This would be over thousands of bet not hundreds.


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Brian Frew
(@bfrew7)
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21/01/2020 6:43 pm  

Thanks a lot Andrew and Michael for the thought provoking information.  I am very definitely on the conservative end of the spectrum, so I will definitely not now be looking to aggressively increase my stake size.  I currently have a "betting bank"  of approximately £3,800, so I think I can just about justify a stake size of £40.  I certainly won't be looking to increase it any time soon!

With regard to the tweaked version of Michael's webinar approach that I alluded to earlier, I have now decided to do it two ways, one being Kelly at 1% of £1,000 (i.e. starting stake of £10).  I'll do that on Smarkets, to keep it totally separate from my Betfair activity.  (They also allow bets lower than £2 if it comes to that!)  It will take me a while to develop any data on the two approaches, as qualifiers don't occur every day.


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Michael Wilding
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21/01/2020 8:05 pm  
Posted by: @tony-mochrie

If I remember correctly the maximum number of losing bets in a sequence increases as the number bet bets increase, even keeping the same strike rate. This would be over thousands of bet not hundreds.

That's absolutely right. The more bets you have the more statistically likely you are to hit a longer losing sequence.


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Michael Wilding
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21/01/2020 8:06 pm  

@bfrew7 great, sounds like you have a similar attitude to risk as myself 😀 


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AndrewP
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21/01/2020 8:37 pm  

£40 is about 1% of your bank Brian. For a dutch of 50% of the book (i.e. even money) this would be about right assuming you have a 1% advantage (cell D52).

Your dutches range from 32% to 86% of book. At 32% your stake would be 0.47% of bank (cell D34), at 86% it would be 6.25% (cell D88). All highly theoretical of course, but you see how easy it is to over/under stake.

If you were to size your stakes according to odds/chance, the process would be;

1. Work out the book % of your selections

2. Look up the % of bank to stake (assuming say 1% advantage)

3. Apportion that stake over the selections so as to return the same amount (straight dutch)


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Brian Frew
(@bfrew7)
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27/01/2020 11:55 pm  

Here is the link to last week's results... https://www.dropbox.com/scl/fi/5358rup73ygd5gt0a2df3/Andrew-P-s-Revised-DutchSaver-Record-Sheet-till-26-Jan-20.xlsx?dl=0&rlkey=k6jlx2okwk1gp4no5f6fc9uen

I've had to totally reset my computer after a Windows 10 crash, so I've been a bit busy with that.

I had a downturn last week, as can be seen from the figures.  I'm going to adopt Andrew's approach (see above) in future.  I've finished the book Andrew and totally get it now.


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