Percentage Of Bankroll To Risk Based On Expected R.O.I.? - Sports Betting

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Percentage Of Bankroll To Risk Based On Expected R.O.I.?

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08-06-2016 , 05:17 PM

Navrark

journeyman

Join Date: Jan 2010 Posts: 254

If I know what my R.O.I. is for a particular bet, is there a mathematical equation that determines the most optimal bet size? For example, let's say that my R.O.I. for XYZ bet is 10%. How do I figure out what the optimal bet size would be?

I spent quite some time Googling for the answer, and I didn't find one. All I find is articles on the Kelly Criterion. But the Kelly Criterion is based on win rate and not R.O.I.. I can gauge the R.O.I. for a bet much more accurately than I can gauge the win chance for a bet.

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08-06-2016 , 05:38 PM

thewoatwoat

enthusiast

Join Date: Jul 2016 Posts: 69

so you know the outcomes of things you bet on prior to betting on them? must be nice

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08-06-2016 , 06:13 PM

slice420

newbie

Join Date: Jan 2016 Posts: 19

Put the R.O.I. into the equation.

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08-06-2016 , 06:58 PM

Navrark

journeyman

Join Date: Jan 2010 Posts: 254

Quote:

Originally Posted by thewoatwoat

so you know the outcomes of things you bet on prior to betting on them? must be nice

I'm not saying that I know the outcome of each specific bet. If I did, I would wager 100% of my bankroll every time.

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08-06-2016 , 07:04 PM

Navrark

journeyman

Join Date: Jan 2010 Posts: 254

Quote:

Originally Posted by slice420

Put the R.O.I. into the equation.

I don't understand how to do that.

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08-06-2016 , 07:39 PM

Navrark

journeyman

Join Date: Jan 2010 Posts: 254

I'm doing research now on how the Kelly Criterion is applied to Blackjack. In Blackjack the player inevitably loses more hands than the dealer, so the win rate cannot be used to apply Kelly to Blackjack. Instead, it seems that Kelly is calculated not by wins but rather by units won. So if over 200 hands a player wins 101 units and loses 99 units, the player is considered to hold a 1% edge.

Therefore, by considering units won/lost as opposed to bets won/lost, the Kelly Criterion could be applied to Sports Betting in a way that might work well for me.

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08-06-2016 , 07:59 PM

slice420

newbie

Join Date: Jan 2016 Posts: 19

I thought you meant estimated ROI for the bet. You can get your estimated win% from the ROI estimate, but why not do the reverse?

Are you choosing the same edge for each bet to keep it simple or because you can't come up with better estimates?

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08-06-2016 , 08:03 PM

andr3w321

adept

Join Date: Jul 2007 Posts: 1,148

Use http://sportsbettingcalcs.com/#roi_calculator to convert ROI to win percentage then plug into the Kelly calculator. I would recommend 1/4 to 1/2 kelly

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08-06-2016 , 09:47 PM

Sabaneta

adept

Join Date: May 2009 Posts: 1,175

Quote:

Originally Posted by Navrark

no you can't.

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08-06-2016 , 09:47 PM

#10

slice420

newbie

Join Date: Jan 2016 Posts: 19

Quote:

Originally Posted by Navrark

???
Full Kelly would be betting the estimated R.O.I.% as % of bankroll if the bet is even money and multiplying or dividing that percentage by something if the line isn't +100. Win rate and odds affect ROI%, but ROI% doesn't affect win rate.

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08-07-2016 , 12:46 AM

#11

Navrark

journeyman

Join Date: Jan 2010 Posts: 254

Quote:

Originally Posted by slice420

I choose a different R.O.I. for each bet based on my past stats.

Quote:

Originally Posted by andr3w321

Use http://sportsbettingcalcs.com/#roi_calculator to convert ROI to win percentage then plug into the Kelly calculator. I would recommend 1/4 to 1/2 kelly

This was beautiful, thank-you! This was exactly what I needed!

My historical data told me that I had approximately a 21.96% R.O.I. on the Chicago White Sox, to win the first half today. I ended up betting 5% of my bankroll on it. However, the Kelly Criterion tells me that it would have been better to bet almost twice as much, 9% of my bankroll, using half Kelly! The Sports Betting calculator that you provided determined that a 21.96% R.O.I. = 55.69% win percentage.

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08-07-2016 , 11:54 AM

#12

slice420

newbie

Join Date: Jan 2016 Posts: 19

The blackjack example was terrible, and Kelly isn't calculated by units won.

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08-07-2016 , 12:17 PM

#13

Sabaneta

adept

Join Date: May 2009 Posts: 1,175

Quote:

Originally Posted by Navrark

My historical data told me that I had approximately a 21.96% R.O.I. on the Chicago White Sox, to win the first half today. .

I'd suggest working harder on your model.

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08-13-2016 , 11:31 AM

#14

Poogs

Pooh-Bah

Join Date: Aug 2009 Posts: 4,501

You noobs always put the cart in front of the horse. Dealing with Kelly should be like the last thing you worry about. Especially if you think you have over 20% ROI on an MLB side (and dont even know how ridiculous that is.) Youre honestly like a solid 2 or 3 years away from even starting to worry about kelly and using it correctly. Right now your kelly stake is a big fat 0. Ive made six figures betting on sports for a few years in a row now and have honestly used the kelly formula maybe two or 3 times in my life. You should be bumping up against max bet limits for the first few years of doing this full time, at least.

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08-13-2016 , 11:49 AM

#15

Mihkel05

banned

Join Date: Jul 2015 Posts: 4,835

Nothing like a fresh glass of POOgs in the morning to liven things up.

You're wrong, but whatever.

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08-13-2016 , 04:49 PM

#16

The IRS

journeyman

Join Date: Apr 2006 Posts: 241

I think the part about max bet limits is usually pretty accurate but what if you have like 20 locals that let you bet 250 a prop?

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08-13-2016 , 11:22 PM

#17

Poogs

Pooh-Bah

Join Date: Aug 2009 Posts: 4,501

I can very easily get down like 2kish on props without having to deal with a ton of diff sites. I actually only deal with one guy now, mostly. Sure im not putting 2 million in play in a day, but its more than enough for me and, knock on wood, doesnt seem to be going anywhere any time soon.

Im in a good mood and I actually have to thank you thremp. Honestly you and your buddies really changed my life in a meaningful way. Im a real, bona fide professional sports better making that doctor guap and it would never have been possible without you and this little message board. So, thanks guy!

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08-14-2016 , 12:05 AM

#18

Sabaneta

adept

Join Date: May 2009 Posts: 1,175

So guy just likes to give you money forever?

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08-14-2016 , 12:15 AM

#19

Poogs

Pooh-Bah

Join Date: Aug 2009 Posts: 4,501

hes not the one taking my action. I dont deal directly with bookies anymore. its complicated, I dont think youd understand Travis.

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08-14-2016 , 12:24 AM

#20

Sabaneta

adept

Join Date: May 2009 Posts: 1,175

Yea I've done that.

Is it the bookies that send you W2's or what?

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08-14-2016 , 11:14 AM

#21

Poogs

Pooh-Bah

Join Date: Aug 2009 Posts: 4,501

I deal with one guy. He deals with many many guys. I missed you guys.

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08-14-2016 , 07:40 PM

#22

Navrark

journeyman

Join Date: Jan 2010 Posts: 254

So, after some detailed analysis I realize that calculating Kelly by R.O.I. isn't going to work. I can definitely tell that certain bets have a higher R.O.I. than others, but I don't have nearly enough historical data to determine exactly what the R.O.I. for each bet is. Instead, I've decided to go ahead with 25% and 50% Kelly bankroll management, using win rate as a judge. That is in addition to my 1% and 2% bankroll management plans.

Thanks for the help!

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08-15-2016 , 07:11 AM

#23

spooner90

old hand

Join Date: Sep 2011 Posts: 1,776

I've been a full time sports bettor for 18 months

Stick to 1% and remember your image is key

Regards

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08-15-2016 , 10:28 AM

#24

Iowa!

old hand

Join Date: Jun 2009 Posts: 1,615

Quote:

Originally Posted by spooner90

I've been a full time sports bettor for 18 months

Stick to 1% and remember your image is key

Regards

So you want to be doing this until you are 70 like Post Oak?

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08-17-2016 , 04:59 PM

#25

NajdorfDefense

Carpal \'Tunnel

Join Date: Feb 2003 Posts: 17,563

Quote:

Originally Posted by spooner90

I've been a full time sports bettor for 18 months

Stick to 1% and remember your image is key

Regards

Christ, I bet more than that on Rags to Riches in the Belmont at +430. [not to mention at +800 at vip, lolz]

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