Using kelly with tennis

http://www.seriousbet.co.uk/calculators/kelly_staking

eg

you have bank of £100

you think Almagro should be 1.90

He can be backed @2.0 ( but you pay 5% commission)

Value index = 102.63

Stake= 2.77% of bank which is £2.77

But if you thought he he was a 1.80 chance then the recommended stake is calculated as £8.76

thanks mate

pricing up matches accurately and consistently is the hard bit

Kelly only works if you have a very good idea of what your long term edge is. If you are just guessing you will get screwed.

It is an excellent weapon in the gamblers arsenal. But unless you are experienced at using it you can take yourself out.

I've always been wary of it, but tried it anyway.

I put in available price as 3.0 and my assessment as 2.0 ...... it said put nearly half your bank on it.


Did I do something wrong?

I prefer to use it in reverse.

Twice my bank?

No, use the formula in reverse.

Rafa, nothing wrong with that, you would've doubled your bank within 52 minutes tonight ;-)

seriously: using Kelly, or fractional Kelly, is a good way if you set a maximum stake in order to protect yourself from extreme overestimations of your edge

All right Aga mate, you know I'm a simple level stakes, straight up guy, I'll give it a whirl, but I've had a few right now.

I just can't. I'm a real long-hand merchant when it come to the maths but I'll get there eventually, but I just can't give it the perceived price angle, especially the way I bet.

You know, Aga, I price up what I think the market will be......

Rafael Nadal 18 Apr 20:12


I've always been wary of it, but tried it anyway.

I put in available price as 3.0 and my assessment as 2.0 ...... it said put nearly half your bank on it.


Did I do something wrong?



Yes, that should be 25%

Lori.

I pu tin 3 as available, 2 as my assessment and 47% of bank is suggested as stake.

Win probability of 50%?

You're doing something wrong, but I can't work out what, I've done it on two other sites before my post and checked on the one you used, all came to 25% of bank fwiw (without commission)

Think you're getting exactly double the required number which is odd.

http://www.sbrforum.com/Betting+Tools/Kelly+Calculator.aspx
http://www.albionresearch.com/kelly/default.php

No, I see it. I put in 2 as opposed to 50%.


Still, that is basically my staple bet, I can't be betting 25% of my bank....... but if Aga likes it I'm sure it works for most people.

It works for those who are reasonably good at estimating real probabilities - others who may be successful by just seeing "this is value" without being able to quantify it are probably better off playing level stakes.

Actually, I determine my stakes by first estimating my "true odds", then determining a confidence interval - this is a completely qualitative step so don't ask me what kind of level of confidence I use, it's just an interval I feel reasinably good about. If the market's odds are outside of that interval, I'll base my stake on the boundary of the interval that's closer to the market price, implicitly acknowledging that the true odds are probably somewhere between my estimate and the market. Using these numbers, I apply quarter Kelly with a cap of 5% of my bank. I could probably play more aggressively but am comfortable with that and still do better than these guys :-) :

http://www.latimes.com/business/la-fi-gambling-fund17-2010apr17,0,2021337.story

That breaks it down better for me, Rekord, sounds very prudent.


Odd that the US authorities would allow it to be invested in knowing they were punting on Betfair.

how does this Kelly theory work ?

http://en.wikipedia.org/wiki/Kelly_criterion

http://forum.sbrforum.com/handicapper-think-tank/29009-expected-value-vs-exp...

thanks lorry

wow tough to get hang off.

wow tough to get hang off.

2nd one is a fantastic explanation imo. Even if you don't follow the maths (many people will, many wont), the logic is really helpful to get an idea what's going on.

the key is to try to maximise the expected value fo the logarithm of your notional bank

A very erotic name for a thread.