Seconded. Also, in the second picture, that line is missing, so it seems that it is just Zvi complaining about the “win probability”?
My guess is that the numbers (sans the weird negative sign) might indicate the returns in percent for betting on either team. Then, if the odds were really 50:50 and the bookmaker was not taking a cut, they should be 200 each? So 160 would be fair if the first team had a win probability of 0.625, while 125 would be fair if the other team had a win probability of 0.8. Of course, these add up to more than one, which is to be expected, the bookmaker wants to make money. If they were adding up to 1.1, that would (from my gut feeling) be a ten percent cut for the bookie. Here, it looks like the bookie is taking almost a third of the money? Why would anyone play at those odds? I find it hard to imagine that anyone can outperform the wisdom of the crowds by a third. The only reason to bet here would be if you knew the outcome beforehand because you had rigged the game.
This is all hypothetical, for all I know the odds in sports betting are stated customarily as the returns on a 70$ bet or whatever.
Those odds are in the confusing “American format”, in which a positive number is “how much would you win (in addition to your bet amount) on a $100 bet”, and the negative number is—careful here! -- how much would you have to bet in order to win $100, again in addition to getting your bet back. There are calculators to get the equivalence, since—especially for the negative odds—it’s not real intuitive. So a 50⁄50 event should be +100 each way, and of course it never is. In this case, −160 would be fair odds for a 60% chance event, and +125 would be fair for a 44.4% chance event, giving a “hold” of 4.4% (60+44.4 − 100), which honestly isn’t terrible as such things go.
I think the %win thing on that screen might be from a different source than the betting odds altogether in this case; the classic 50⁄50 bet is generally priced at −110/-110, which works out to a 4.8% hold.
You’ll note that because of the way the +/- odds work, it’s really hard to instantly grasp how good/bad most odds are. (It’s not “halfway between the two”, for one thing.) In Europe/Asia the common format is a decimal number telling you how much you multiply your stake by, including getting the stake back, so those would be [checks online calculator] 1.63 and 2.25. The single advantage of the American system is that you can see what a fair bet should be, because one is just the negation of the other. (For two-way results.) In this case it would be +-138.5.
Seconded. Also, in the second picture, that line is missing, so it seems that it is just Zvi complaining about the “win probability”?
My guess is that the numbers (sans the weird negative sign) might indicate the returns in percent for betting on either team. Then, if the odds were really 50:50 and the bookmaker was not taking a cut, they should be 200 each? So 160 would be fair if the first team had a win probability of 0.625, while 125 would be fair if the other team had a win probability of 0.8. Of course, these add up to more than one, which is to be expected, the bookmaker wants to make money. If they were adding up to 1.1, that would (from my gut feeling) be a ten percent cut for the bookie. Here, it looks like the bookie is taking almost a third of the money? Why would anyone play at those odds? I find it hard to imagine that anyone can outperform the wisdom of the crowds by a third. The only reason to bet here would be if you knew the outcome beforehand because you had rigged the game.This is all hypothetical, for all I know the odds in sports betting are stated customarily as the returns on a 70$ bet or whatever.
Edit: seems I was not very correct in my guess.
Those odds are in the confusing “American format”, in which a positive number is “how much would you win (in addition to your bet amount) on a $100 bet”, and the negative number is—careful here! -- how much would you have to bet in order to win $100, again in addition to getting your bet back. There are calculators to get the equivalence, since—especially for the negative odds—it’s not real intuitive. So a 50⁄50 event should be +100 each way, and of course it never is. In this case, −160 would be fair odds for a 60% chance event, and +125 would be fair for a 44.4% chance event, giving a “hold” of 4.4% (60+44.4 − 100), which honestly isn’t terrible as such things go.
I think the %win thing on that screen might be from a different source than the betting odds altogether in this case; the classic 50⁄50 bet is generally priced at −110/-110, which works out to a 4.8% hold.
You’ll note that because of the way the +/- odds work, it’s really hard to instantly grasp how good/bad most odds are. (It’s not “halfway between the two”, for one thing.) In Europe/Asia the common format is a decimal number telling you how much you multiply your stake by, including getting the stake back, so those would be [checks online calculator] 1.63 and 2.25. The single advantage of the American system is that you can see what a fair bet should be, because one is just the negation of the other. (For two-way results.) In this case it would be +-138.5.