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Happy new year and some basic sports betting math

03 January 2013By: admin

Hope everyone that is reading has had a great new years celebration, I know that I did, maybe a little too great! :) Couple of Vodka shots too many and you have a recipe for an awesome evening.

Also hope that you readers have been following my bets, as we went 2 for 2 on our last predictions. I have another prediction coming up, but first I would like to write a little about some basic sports betting math that hopefully can help you understand what is going on when I analyze betting objects and hopefully get you to try your hand at betting with your own tips in the future.

Let us take a look at the Dota 2 G-League E-Sports odds that Pinnacle Sports has put up for the upcoming matches, more specifically, let us look at the odds given in the game between Invictus Gaming and LGD.cn. Here you can bet on the winner of the match, and the odds on Invictus Gaming winning the BO5 is 1.235 and the odds on LGD.cn winning the BO5 is 4.370. For those who are unfamiliar with odds, this means that if you bet $1000 on Invictus Gaming winning, you will get back $1235 (your $1000 bet, and your winnings of $235). If you bet $1000 on LGD.cn to win, you will get back $4370 if you win (your $1000 bet and $3370 in winnings).

Most people believe that when you are making bets on sports betting outcomes (and this is no different when betting on e-sports), you are trying to bet on the team that is going to win. However, if this where the case, and this would make you a winner, simply betting on the favorite, in this case, Invictus gaming, who are the overwhelming favorite, would be the team everyone would place their money on.

However, the idea of betting is not to pick the team that you think will win, but picking the team that you believe gives you odds that are better than the chance they have of winning the game. Sports betting is a game of small edges and finding these small errors that bookmakers make are crucial in finding profitable bets. Let me show you how odds and probability in this case ties together:

Odds and implied win probability
Invictus Gaming, 1.235 (Win probability = 1/1.235 = 80.97%)
LGD.cn, 4.370 (Win probability = 1/4.370 = 22.88%)

The odds that is presented to us, if they where fair, would give us the impression that the bookmaker believes that Invictus Gaming would win 80.97% of the time and LGD.cn would win 22.88% of the time. But some of you might notice that these percentages does not add up to 100%, which is the requisite for probability. It adds up to 103.85% to be exact, and the 3.85% is the theoretical hold, or juice if you like, that the sportsbook takes to make money. The implied win probabilities are as follows:

Invictus Gaming, 80.97%/103.85% = 77.97%
LGD.cn, 22.88%/103.85% = 22.03%

These implied win probabilities are what the sportsbook believes are the "true" win probabilities, and they subtract a little from the odds that you are offered, so to make a little cut from the betting:

Invictus Gaming, 1/77.97% = 1.283
LGD.cn, 1/22.03% = 4.538

What is the next step?
So what does all this number crunching help us? From here, you can do a lot of stuff. First of all, being able to know what probabilities the bookmaker assigns to the teams, helps us basing our estimations. If we try to estimate the chance of LGD.cn winning, we need to find that to be higher than 22.03% to be able to make a profitable bet at Pinnacle Sports odds. This goes hand in hand with what I said earlier about not picking winners, but picking objects that have a larger chance of winning than the odds presented to you suggests.

If you believe that the oddsmakers at Pinnacle Sports are among the best, you can base of their odds when looking at other sites for good bets. If you do the calculations above, and find odds on Invictus Gaming on another site that is > 1.283 or odds on LGD.cn that is > 4.538, you can make a profitable bet.

Remember though, that odds at sportsbooks change, and if you do these calculations one day, and you check the odds the next day at Pinnacle and find that the odds on Invictus Gaming has changed to 1.352, that does not mean you have a good bet. The reason for this change might be because of a player that has gotten ill, change in rules or some other thing that favors LGD.cn´s chances.

If you want to learn more, we have added a sports betting math section in our sports betting guide. Check it out!