Kelly Criterion

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sarkec
Posts: 54
Joined: Thu Sep 29, 2016 12:38 pm

Hello Everyone,

I would like to use Kelly Criterion but I do not manage to use it at more bets at the same time.
For example: I would like to bet at 20 matches what are playing at the same time.
How do you calculate your stake for more matches with Kelly Criterion?

Thanks
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Kafkaesque
Posts: 886
Joined: Fri Oct 06, 2017 10:20 am

sarkec wrote:
Thu Nov 16, 2017 10:05 am
Hello Everyone,

I would like to use Kelly Criterion but I do not manage to use it at more bets at the same time.
For example: I would like to bet at 20 matches what are playing at the same time.
How do you calculate your stake for more matches with Kelly Criterion?

Thanks
First things first. Given this is a trading forum and you write "bets", then just to be clear, are you talking about trades or bets?

Edit: Also, I assume, your question is based on that the total of the 20 matches being more than 100%. Correct???
Nero Tulip
Posts: 686
Joined: Wed Apr 15, 2009 5:29 pm

Betting and trading is the same thing isn't it ? :mrgreen: (It actually is.. anyway..cough.....)

As a user of Kelly, for my trading, some tips -

Don't use your whole bank, decide on a much smaller notional bank that you will apply to standardise your staking levels. Will leave sizing of that up to your idea of what's sensible. Mine varies on liquidity of market, and then on the biggest of markets, doesn't go above 1% of net worth, usually it's far smaller than this.

In practice, this means you have 20 matches, the bank roll is (for example) 1k for each, you then run your calculation using that. Don't go mad changing the bankroll size quickly if you make money, you have all the brilliant pitfalls that any staking method has which can lead to ruin, so win with consistency.

No doubt someone will arrive on thread and use the word "fractional"...I much prefer "full". Fractional just says that your idea of fair value is that fraction closer to the market, there's little point in doing this. If the heat is too high, downsize your bankroll to a better level and stick with that.
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Kafkaesque
Posts: 886
Joined: Fri Oct 06, 2017 10:20 am

Nero Tulip wrote:
Thu Nov 16, 2017 10:30 am
Betting and trading is the same thing isn't it ? :mrgreen: (It actually is.. anyway..cough.....)
Debated at length elsewhere, but it most certainly isn't the same when talking Kelly.
Nero Tulip wrote:
Thu Nov 16, 2017 10:30 am
Don't go mad changing the bankroll size quickly if you make money
I'm sorry mate, but this is the EXACT OPPOSITE of the whole point of Kelly!!!
sarkec
Posts: 54
Joined: Thu Sep 29, 2016 12:38 pm

Kafkaesque wrote:
Thu Nov 16, 2017 10:18 am
sarkec wrote:
Thu Nov 16, 2017 10:05 am
Hello Everyone,

I would like to use Kelly Criterion but I do not manage to use it at more bets at the same time.
For example: I would like to bet at 20 matches what are playing at the same time.
How do you calculate your stake for more matches with Kelly Criterion?

Thanks
First things first. Given this is a trading forum and you write "bets", then just to be clear, are you talking about trades or bets?

Edit: Also, I assume, your question is based on that the total of the 20 matches being more than 100%. Correct???
Correct!

Nero Tulip, Thank you, I understood!
Nero Tulip
Posts: 686
Joined: Wed Apr 15, 2009 5:29 pm

Kafkaesque wrote:
Thu Nov 16, 2017 10:37 am
Nero Tulip wrote:
Thu Nov 16, 2017 10:30 am
Betting and trading is the same thing isn't it ? :mrgreen: (It actually is.. anyway..cough.....)
Debated at length elsewhere, but it most certainly isn't the same when talking Kelly.
Nero Tulip wrote:
Thu Nov 16, 2017 10:30 am
Don't go mad changing the bankroll size quickly if you make money
I'm sorry mate, but this is the EXACT OPPOSITE of the whole point of Kelly!!!
With respect, you are wrong about kelly and trading. And I'm not sure you understood my original post either. Anyway, the use of it isn't obvious for trading and arguably, it isn't 'keeping it simple', perhaps there are higher priorities for most traders. Good luck.
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Kafkaesque
Posts: 886
Joined: Fri Oct 06, 2017 10:20 am

Nero Tulip wrote:
Thu Nov 16, 2017 10:47 am
With respect, you are wrong about kelly and trading. And I'm not sure you understood my original post either. Anyway, the use of it isn't obvious for trading and arguably, it isn't 'keeping it simple', perhaps there are higher priorities for most traders. Good luck.
With the same respect ;) please explain how I'm wrong and what I misunderstood?

As I understand your original post, you're giving advice on Kelly, while actually advocating using a form of unit-based system. And using it yourself, without realizing it.

A key component of Kelly is the maximization of the usage one's bankroll to grow it as fast as possible with as small a risk of ruin as possible. Advising to not use your whole bankroll and not adjust your bankroll/staking when the bankroll grows is just plain wrong. Not bad advice per se. That's a matter of opinion. However, in terms of a response to a Kelly question, it's incorrect.

@Sarkec, you never actually answered whether your question is intented for betting or trading :)
sarkec
Posts: 54
Joined: Thu Sep 29, 2016 12:38 pm

My question is for betting 20 selections with a bankroll of 1000 E. The selections are at the same time.
Nero Tulip
Posts: 686
Joined: Wed Apr 15, 2009 5:29 pm

Kafkaesque wrote:
Thu Nov 16, 2017 11:17 am
Nero Tulip wrote:
Thu Nov 16, 2017 10:47 am
With respect, you are wrong about kelly and trading. And I'm not sure you understood my original post either. Anyway, the use of it isn't obvious for trading and arguably, it isn't 'keeping it simple', perhaps there are higher priorities for most traders. Good luck.
With the same respect ;) please explain how I'm wrong and what I misunderstood?

As I understand your original post, you're giving advice on Kelly, while actually advocating using a form of unit-based system. And using it yourself, without realizing it.

A key component of Kelly is the maximization of the usage one's bankroll to grow it as fast as possible with as small a risk of ruin as possible. Advising to not use your whole bankroll and not adjust your bankroll/staking when the bankroll grows is just plain wrong. Not bad advice per se. That's a matter of opinion. However, in terms of a response to a Kelly question, it's incorrect.

@Sarkec, you never actually answered whether your question is intented for betting or trading :)
I didn't suggest any unit based system. I'm advocating use of full kelly! Using a notional bank. The key is not to change the bank, the bet sizes obviously would change massively because it is full kelly. This is the ideal way of dealing with high repetition of trials, multiple markets and varying levels of liquidity as we are in betting markets. 10 years plus using this myself tells me it is far more optimal than level / unit stakes.. but the implementation for trading isn't obvious.
convoysur-2
Posts: 1110
Joined: Thu Jan 12, 2012 10:00 am

sarkec wrote:
Thu Nov 16, 2017 10:05 am
Hello Everyone,

I would like to use Kelly Criterion but I do not manage to use it at more bets at the same time.
For example: I would like to bet at 20 matches what are playing at the same time.
How do you calculate your stake for more matches with Kelly Criterion?

Thanks
i could never find a way to use kelly like that with alot of bets-trades-
percentage -or percentage liability may work best for you.i find if you have 20 coming up on the same day say your bank is 700 and your using 5% its better to make them all 35 each,and recalculate at end of that batch of bets-trades
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Kafkaesque
Posts: 886
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sarkec wrote:
Thu Nov 16, 2017 11:31 am
My question is for betting 20 selections with a bankroll of 1000 E. The selections are at the same time.
If it's betting, my first piece of advice would be to join a forum for betting :) You're likely to get better and more varied responses. Not that you shouldn't stick around here :) Second piece of advice. Unless you're in this spot because it's all very short prices, you really shouldn't be going over 100% with 20 selections. You're either wrong about your calculation of chances for your selections, or you're a God among men with picking selections ;) If your "probability of success" is derived from your opinion, take a step back and consider whether you're overestimating your edge over the price. If it's derived from past results/bets, look into p-value to see how many bets it actually takes before results can be considered statistically relevant and sustainable. It's a lot more than you'd expect!

Just my two cents, but as it were, if we assume, your calculations are correct, you've got a few options:

1) Fractional Kelly. Yep Nero, I came along and said it ;) Simply adjust each bet down by a certain percentage to coincide with 100% total.

2) Choose the selections with the highest recommended percentage, and leave the rest out. These should be the ones with the best combination of high edge and low volatility.

3) Choose the selections with the shortest prices, and leave the rest out. Lowest volatility and thus chance of building your bankroll.

Now, here's where I do agree with Nero. I'm not a fan of fractional Kelly. I would suggest option 2, closely followed by option 3. I only mention fractional Kelly, because using full Kelly with option 2 absolutely demands that you know what you're doing. If you're in any doubt, as to whether your basis of calculations is rock solid, then I'd go with option 1.
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Kafkaesque
Posts: 886
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Nero Tulip wrote:
Thu Nov 16, 2017 11:35 am
I didn't suggest any unit based system. I'm advocating use of full kelly! Using a notional bank. The key is not to change the bank, the bet sizes obviously would change massively because it is full kelly. This is the ideal way of dealing with high repetition of trials, multiple markets and varying levels of liquidity as we are in betting markets. 10 years plus using this myself tells me it is far more optimal than level / unit stakes.. but the implementation for trading isn't obvious.
You're advocating using full Kelly to calculate the stake/units staked within a unit staking system. Not actually using full Kelly. Because, yeah changing the bankroll is absolutely key. The point of Kelly is to grow the bank exponentially, which can only be done by adjusting the bank.

I do agree that the implementation isn't obvious for trading. Said as much in the difference between trading and gambling thread.
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Kafkaesque
Posts: 886
Joined: Fri Oct 06, 2017 10:20 am

Before coming off as too much of a c***, I should qualify the above by noting that I'm not necessarily saying, you're doing anything wrong with your approach to BR management and staking. I am however adament that your terminology and use is wrong, which by extention made it bad advice to the question at hand. 10 years of doing something doesn't - automatically - make you good at it. I've been making a living for the best part of two decades on a, at various times, combination of poker, betting, day trading, and sports trading. And I'm still very much learning. Every day! More than anything, what I've learned over all those years is to always keep an open mind. Because I've made plenty - plenty! - of mistakes and have held mistaken believes on theories and approaches for any given time before seeing the light. I do hear and acknowledge your approach to BR. I happen to disagree with it as completely ideal, but it's absolutely fine and solid. In the end, all I'm saying is, that I see room for improvement, given that you seem - to me at least - not to have fully come to terms with the workings of Kelly. You're welcome to stick to your steadfast approach of having a full grasp of it, in which case I can only close with the same end that one of your first response to me had. Good luck.
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Derek27
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Joined: Wed Aug 30, 2017 11:44 am
Location: UK

sarkec wrote:
Thu Nov 16, 2017 10:05 am
Hello Everyone,

I would like to use Kelly Criterion but I do not manage to use it at more bets at the same time.
For example: I would like to bet at 20 matches what are playing at the same time.
How do you calculate your stake for more matches with Kelly Criterion?

Thanks
Wikipedia explains how to use KC for multiple bets (by that I don't mean accumulators), but it's quite complex !

https://en.wikipedia.org/wiki/Kelly_criterion
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Kafkaesque
Posts: 886
Joined: Fri Oct 06, 2017 10:20 am

Derek27 wrote:
Thu Nov 16, 2017 1:10 pm
Wikipedia explains how to use KC for multiple bets (by that I don't mean accumulators), but it's quite complex !

https://en.wikipedia.org/wiki/Kelly_criterion
What you're talking about is multiple bets within the same market, though. Or???

Different from this spot where it's multiple bets in independent markets.

FWIW, a more explanatory approach, even if still sligthly complex for the problem, if it helps anyone:

https://www.pinnacle.com/en/betting-art ... CB3KNYN9CJ
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