The Logic Of Sports Betting

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1. PaulRobinsonNov 2025
   I am a semi-professional gambler, based in the UK. To parse that statement: I have a day job; I make about as much income from software that trades on betting exchanges as I do from the day job, except that income is tax free (because UK law does not recognise it as a taxable trade - another debate); and I spend a lot of time watching, reading and understanding changes in the gambling industry because a significant chunk of my savings income comes from it.

   The UK went through almost everything the US is going through right now some years ago, where problem gambling led to suicides and people struggling to pay bills. Multiple measures have been taken that seem to have directly helped that situation: VIP programs have been scrapped; advertising is being limited; and, you may have to prove you can afford to bet the levels you're betting at to an operator, which is an incredibly unpopular move (who wants to send their pay slips to their bookie?), but does seem to have quelled things a little.

   However there is more to do, and there is something you can do right now if you are losing money and want to reduce the impact these products have on you.

   Stop playing casino and video slot games. Focus on sports only.

   The myth is that the problem gamblers are losing their money on 2nd Division Nigerian netball games in the middle of the night. Yes, there are some people who are looking for sports action all the time, but that's not the biggest source of problems.

   With sports, you have a little time to think. I recommend not playing in-play unless you have automated that solution to find EV and its executing for you (I know people who make money doing this on Betfair in the UK). Bet before game only, and you will have a built-in "cool off" period.

   You don't get that with casino games or video slots. Its relentless, and you can lose thousands an hour before you even realise what is happening.

   And then, there's EV. Expected Value. Sometimes (actually, kinda often), the odds a bookmaker puts up are a bit wrong.

   Not every price, it might be a prop bet on a particular player, and they're putting a price up on a Monday for a Saturday game, and you have a spreadsheet that dings something and tells you what the kelly stake should be and you put 1% of your bankroll on it, and then you might sell it back on Saturday morning when the market has got right or you let it ride (and there's maths to tell you when to do that and when not), and you ride some variance but make money.

   That's not possible on casino or video slot games. They just bleed you. There is no EV. If you win, you got lucky (the scientific name for this is "experienced positive variance"), and you should run away quickly before you lose it back. But the sure way to win on those games is the same as in Wargames: don't play at all.

   I'm biased, I realise that, but I would love to see the outlawing of casino and slot games on mobile.

   I would also like to see more education in schools around probability and statistics (the founder of SIG, a storied institution who is now a market maker on Kalshi, the prediction market platform), argues that the fascination with calculus in schools might have helped during the space race, but today we need people to really understand Bayes theorem more than anything else. I agree.

   If you want to start your own education in how to bet a little smarter and lose a little less, I can recommend The Logic of Sports Betting [0] and its sequel Interception [1]. I also like Dan Abrams' book [2], that talks about expected growth, not just exepcted value.

   These are not get rich quick schemes, but it will give you an idea of what goes on in the minds of people who try and take this all very seriously. You'll still need to think about modelling and how to get your own prices to compare with those you're being offered, but if you're not prepared to do that work, what is it you're actually doing?

   [0] https://www.amazon.com/Logic-Sports-Betting-Ed-Miller/dp/109...

   [1] https://www.amazon.com/Interception-Secrets-Modern-Sports-Be...

   [2] https://www.amazon.com/But-How-Much-Did-Lose-ebook/dp/B0DRZ2...

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2. vgeekOct 2025
   The Logic of Sports Betting by Ed Miller is probably a good start.

   Parimutuel vs house odds is probably a good start in seeing how odds change in different types of markets. Monte Carlo simulations will be useful in coming up with your own tissue odds. Then it is the matter of backtesting and comparing your derived odds versus the books' by looking at things like Closing Line Value, Margin of Error and Return on Investment.

   For data, check out Kaggle. Learn how to scrape and circumvent platforms like PerimeterX, Recaptcha and Cloudflare. There are dozens of sites that provide historical odds data, even more basic sports statistic data.

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