A Look at Gambling Math

  -   January 19th, 2012   
Posted in: Articles, Industry News, Offline Poker News, Players

• Tweet
• Email
• Sharebar

• Tweet
• Email

The Mathematics of Sports Betting

Unless you are an expert handicapper or the luckiest guy on Earth, the sportsbooks know they’re very likely to make money off you. People think that betting on sports is like betting on blackjack. The thought process goes like this: if I understand all the math behind a bet, if I play this bet with optimum strategy, I can expect a positive return, I can win more often than I lose. Unfortunately, even a perfect understanding of the mathematics of sports betting won’t turn you into a millionaire by placing sports bets.

Successful sports bettors almost always have an intellectual understanding of betting math and betting odds. Quotes from guys like Mike Orkin, a statistics professor in California, pop up all over the web when you search for gambling advice. Orkin famously instructs that gamblers will never win unless they wrap their heads around the math of the games. That’s pretty cut and dried, straightforward advice.

My blackjack analogy at the beginning is apt, because it was eggheads obsessed with mathematics that worked out winning blackjack strategy in the 60s. Sports are complex, and figuring out the edge a player or team has against another is nothing but applied math.

How Betting Math Works

At its most basic level, understanding betting math means working out your chances of winning a bet and the actual payoff odds provided by the sportsbook. That means calculating your own set of true odds using the odds at the book and the math in your head.

A simple example of calculating true odds is the popular two-team parlay bet. The true mathematical odds of winning a two-team parlay are 3/1. How did we get to that number? You multiply the chances of your team winning the first game (one in two or ½) by the chance of your team winning the second game (also one in two or ½). Do the math: 1/2  x 1/2 =  1/4, or one-in-four. One in four expressed as a fraction is 3/1. You have a one in four chance of just guessing your way to a two-team parlay win.

Apply this to all other parlay bets to figure out the betting math behind parlays.

Using Betting Math to Find Good Bets

Parlays are popular because they’re legal in many states and aren’t high-dollar bets. But are parlays good bets mathematically speaking?

2-team parlays pay off at 13/5 but you actually have a  3/1 chance of winning. The difference comes from the sportsbooks vig. The house edge on a two-team parlay is 10%.

Naturally, the more teams involved in your parlay, the greater the house edge. That’s the opposite of games like slot machines, where the house offers better odds for larger bets. For example, a 3-team parlay pays off at 6/1 even though your actual odds are 7/1. That gives the house a 12.5% advantage.

All this to say that the only smart parlay bet is a two-team parlay that offers you the best possible payout based on the game’s odds. If you can find two games where there is a true powerhouse playing the Little Sisters of the Blind, take that bet for as much as is legal in your state. Otherwise, avoid parlays.

Examples of Good Mathematical Bets

Sports handicappers, professional and amateur, rely on math to make a living. Many of them could care less about the game. They’re interested in probabilities and return on investment, or ROI.

Your typical sports handicapper looks at numbers to better understand how to earn profit placing sports bets over a long period of time. If anyone tells you that math can help them win in the short term, they’re yanking your chain.

The return on any investment is the profit earned divided by the money risked for the investment. For example, if you place 100 $100 bets, and 50 of them turn out in your favor while 50 turn out against you, you’ll actually be down $500, thanks to vigorish. You’ve actually bet $11,000 (with the juice added in) and your investment produced a -4.5 % result. Yes, you end up with $10,500, so your day wasn’t all that bad, but it was still a poor investment.

Using math to fend off the negative effects of the sportsbooks vigorish, a sports bettor has to win at least 53% of every one of his bets. If you can manage to win 53% of your bets, you’ll see +1.2% return on your investment. Invest enough money in your bets, and that 1.2% can mean a lot of cash, of course you’d be better off sticking that money in a decent savings account. The downside being that your bank probably doesn’t comp drinks.

The idea is to consistently win more than 53% of the time. If you win 55% of your bets for a year, you’ll have a +5% ROI, while a 60% success gives you a return of +14.5%. Now you’re in daytrader territory.

Working with a large enough bankroll, a head for math, straightforward bets, and plenty of gambling discipline, it is possible to earn a living at the sportsbook. Unfortunately, to win even 53% of the time, you’d have to be one of the world’s greatest sports gamblers. You might have a lucky day here and there, but to consistently win at 50% (still a losing proposition) is almost unheard of.

Understanding betting math can be a bit depressing, because it shows how the sportsbook has you by the short and curlies, and there’s really no way at all to get a leg up on them over the long run. Use your understanding of math and your sports knowledge to place smart bets from time to time, but don’t expect to win consistently unless you have a freakish mathematical brain.

Tags: Good Mathematical Bets, Mike Orkin, ROI

Comments are closed.