An introduction to betting lines and percentages

[durito]

if he were able to pound out this formula into a more user friendly format, and its proven to be accurate, players would be killing the books

huh

[ZXCVBNM]

too bad, I always enjoyed reading his posts even though I don't really put them in practice so to speak.

[blackf1re]

It's scary how many posters don't understand the simple concept of value. And when you question their records you get flamed to death by fanboys for no apparent reason because hey, they 'post winners'.

[sharpcat]

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Handicappers digest says these guys are on a 1-20 run

[RaginCajun]

hey ganchrow, i dont quite understand what those percentages mean for miami and dallas. what does it mean that miami is around 32% and dallas is around 68%? sorry im new to using math with sports gambling. if i were in that situation, who would i want to bet on?

[biggie12]

good read !

[wrongturn]

The implied line is +216 for Miami and -216 for Dallas. So if you can find a better price than that implied line, then that is your bet! Just don't use it to pick winners because it does not intend to.

[rfr3sh]

hey ganchrow, i dont quite understand what those percentages mean for miami and dallas. what does it mean that miami is around 32% and dallas is around 68%? sorry im new to using math with sports gambling. if i were in that situation, who would i want to bet on?

that is the implied probability pinnacle has come up with 32% for miami and 68%
you would bet on miami if you think they had a greater then 32% chance to win and dallas if you think they had a greater then 68% chance to win

[SadZizou]

Hi everybody...many comparison sites show for a particular event, also the payout of the book.
Am I right if I consider:

Payout=1/no-vig*100

???

[RaginCajun]

What's it intended to do if its not used to pick winners?

[rfr3sh]

To judge if it is a fair line

[RockyV]

Great post. I didn't understand the following comment at all, though:

Unfortunately, unless you’re either betting with friends or a “crossed-market” situation exists across multiple sportsbooks (or, I suppose, you’re still insane enough to play at No-Juice Sportsbook), this is an uncommon occurrence.

Why is playing on a no-juice sportsbook a bad idea? Aren't they basically cheaper than playing on ones with lots of juice, and at least in theory more profitable?

[losturmarbles]

Great post. I didn't understand the following comment at all, though:






Why is playing on a no-juice sportsbook a bad idea? Aren't they basically cheaper than playing on ones with lots of juice, and at least in theory more profitable?

A no-juice sportsbook doesn't exist. They are in the same category as those guys selling $15,000 cars for $3,000 on craigslist. Or that Nigerian uncle you never knew that died and left you a giant fortune, but you need to send the estate administer a fee of $2,500 to process the transfer. A no-juice sportsbook is a no-juice scam operation.

[RockyV]

Thanks, got you.

[THE HITMAN]

Good stuff for the Frosh & Sophs............and a good refresher course for everyone.

[jhol3990]

really need someone doing a guide to the best posts in this forum - spend most of my time mining for this sort of information amongst the banter

[EBone]

I will echo LT's thoughts earlier in this thread. I feel very lucky to have come across Ganchrow. I learned a whole lot from him.

Here's my question though: if my memory serves me correctly, Ganchrow was the driver behind the 1/2 point calculator on the SBR gambling tools apps. Is anyone keeping this up to date? As in, if Ganchrow loaded this in 2009, have the values of each 1/2 point been updated by SBR in each sport? If so, who is keeping this up to date?



E

[allin1]

These kind topics from Granchrow are brilliant. Thanks a lot!

[Inkwell77]

Sure.

Tonight's NBA game at Pinnacle is currently:
Miami +210
Dallas -230

This means that Miami's zero-vig implied probability would be:
100/(100+210) ≈ 32.26%

and Dallas's would be:
230 / (100 + 230) ≈ 69.70%

The total of the implied zero-vig probabilities (also known as the bookie's overround) is 32.26% + 69.70% ≈ 101.96%.

This means that the implied line set probability for Miami is 32.26%/101.96% ≈ 31.64% and for Dallas is 69.70%/101.96% ≈ 68.36%.

Make sense?

fukkin right on!

[wantitall4moi]

As with everything else math related here people need a dictionary or at least get the semantics correct.

There is no set PROBABILITY based on a line. The example given was -230/210 and 'probabilities' of 32% and 69%. All the overage does if give the books theoretical hold based on balanced action at those splits. It surely doesnt mean that Miami has a 'no vig' probability of 69.7% to win the game. What happens if the line moves to -280/265 does Miamis probability magically go to 73.7%? Not hardly, their PROBABILITY to win the game doesnt move one bit, the ODDS did based on people betting the game.

Now if one had a perfectly calibrated machine that was able to actually determine the true PROBABILITY of one team winning and then compared it to the odds then you could find 'value'. But that isnt going to happen. A lot of guys have models but not many are good enough to even start figuring how valid they are let alone using them to determine a fair probability.

This is the same math mumbo jumbo guys have been spouting forever. This is actually pretty generic stuff and the simplest way books use to calculate lines they throw out, at least books that are out right clones of other books. All it is really good for is checking to see how much hold a book is taking out of you when you see a set of lines. A more contemporary example would be today in baseball, as of right now in the Dodgers/cubs game. 5 dimes is -102/108, Pinnacle is +102/108, bookmaker is -117/-103, betonline is -105/-105, and Legends is -110/-110,. So according to this post the odds of Dodgers winning (no vig) range from 48.1% to 53.9%? Same exact match up but one books gives them less than a 50% chance (actually a few of them) while another gives them nearly 54% chance? No it just means one book is taking a 1.41 or so hold on the game, while the other (the one dealing a 20 cent line) is taking 4.45% hold, more than 3 times as much.

The sooner people realize betting odds have ABSOLUTELY NOTHING to do with actual win chance/probability the better off they will be. This post is a good example of showing how books make their money on the odds they offer, it surely doesnt give the actual win probability of one side versus the other. At best it shows what percentage a bettor has to win at the odds they are checking to break even.

EDIT: actually one small correction, the odds for that dodgers cubs game were for the closing lines of the game not current odds for the game.

[Sam Odom]

get this shit off of the forum ... Race , gay & Bieber are the real issues

[chunk]

As with everything else math related here people need a dictionary or at least get the semantics correct.

There is no set PROBABILITY based on a line. The example given was -230/210 and 'probabilities' of 32% and 69%. All the overage does if give the books theoretical hold based on balanced action at those splits. It surely doesnt mean that Miami has a 'no vig' probability of 69.7% to win the game. What happens if the line moves to -280/265 does Miamis probability magically go to 73.7%? Not hardly, their PROBABILITY to win the game doesnt move one bit, the ODDS did based on people betting the game.

Now if one had a perfectly calibrated machine that was able to actually determine the true PROBABILITY of one team winning and then compared it to the odds then you could find 'value'. But that isnt going to happen. A lot of guys have models but not many are good enough to even start figuring how valid they are let alone using them to determine a fair probability.

This is the same math mumbo jumbo guys have been spouting forever. This is actually pretty generic stuff and the simplest way books use to calculate lines they throw out, at least books that are out right clones of other books. All it is really good for is checking to see how much hold a book is taking out of you when you see a set of lines. A more contemporary example would be today in baseball, as of right now in the Dodgers/cubs game. 5 dimes is -102/108, Pinnacle is +102/108, bookmaker is -117/-103, betonline is -105/-105, and Legends is -110/-110,. So according to this post the odds of Dodgers winning (no vig) range from 48.1% to 53.9%? Same exact match up but one books gives them less than a 50% chance (actually a few of them) while another gives them nearly 54% chance? No it just means one book is taking a 1.41 or so hold on the game, while the other (the one dealing a 20 cent line) is taking 4.45% hold, more than 3 times as much.

The sooner people realize betting odds have ABSOLUTELY NOTHING to do with actual win chance/probability the better off they will be. This post is a good example of showing how books make their money on the odds they offer, it surely doesnt give the actual win probability of one side versus the other. At best it shows what percentage a bettor has to win at the odds they are checking to break even.

EDIT: actually one small correction, the odds for that dodgers cubs game were for the closing lines of the game not current odds for the game.

Uh oh, this makes too much sense....be prepared for the broadsides.

[VLR100]

get this shit off of the forum ... Race , gay & Bieber are the real issues

God bless America.

The sooner people realize betting odds have ABSOLUTELY NOTHING to do with actual win chance/probability the better off they will be.

So a +200 bet has, on average, as good a chance of winning as a -200 bet? Damn, why have I been betting favourites all this time? Thanks for the insight.

[mathdotcom]

God bless America.



So a +200 bet has, on average, as good a chance of winning as a -200 bet? Damn, why have I been betting favourites all this time? Thanks for the insight.

No it doesn't

[Sam Odom]

mathy , who is this wantitall fellow ?

[VLR100]

No it doesn't

I know. I was highlighting the absurdity of the quoted statement.

[chunk]

You had to know that one was coming....needed to edit a little more.

[wrongturn]

As with everything else math related here people need a dictionary or at least get the semantics correct.

There is no set PROBABILITY based on a line. The example given was -230/210 and 'probabilities' of 32% and 69%. All the overage does if give the books theoretical hold based on balanced action at those splits. It surely doesnt mean that Miami has a 'no vig' probability of 69.7% to win the game. What happens if the line moves to -280/265 does Miamis probability magically go to 73.7%? Not hardly, their PROBABILITY to win the game doesnt move one bit, the ODDS did based on people betting the game.

Now if one had a perfectly calibrated machine that was able to actually determine the true PROBABILITY of one team winning and then compared it to the odds then you could find 'value'. But that isnt going to happen. A lot of guys have models but not many are good enough to even start figuring how valid they are let alone using them to determine a fair probability.

This is the same math mumbo jumbo guys have been spouting forever. This is actually pretty generic stuff and the simplest way books use to calculate lines they throw out, at least books that are out right clones of other books. All it is really good for is checking to see how much hold a book is taking out of you when you see a set of lines. A more contemporary example would be today in baseball, as of right now in the Dodgers/cubs game. 5 dimes is -102/108, Pinnacle is +102/108, bookmaker is -117/-103, betonline is -105/-105, and Legends is -110/-110,. So according to this post the odds of Dodgers winning (no vig) range from 48.1% to 53.9%? Same exact match up but one books gives them less than a 50% chance (actually a few of them) while another gives them nearly 54% chance? No it just means one book is taking a 1.41 or so hold on the game, while the other (the one dealing a 20 cent line) is taking 4.45% hold, more than 3 times as much.

The sooner people realize betting odds have ABSOLUTELY NOTHING to do with actual win chance/probability the better off they will be. This post is a good example of showing how books make their money on the odds they offer, it surely doesnt give the actual win probability of one side versus the other. At best it shows what percentage a bettor has to win at the odds they are checking to break even.

EDIT: actually one small correction, the odds for that dodgers cubs game were for the closing lines of the game not current odds for the game.

While you are certainly entitled to warn people this is not the calculation for true winning probability, which nobody really knows anyway, Ganchrow did not try to sell people that magic either. He wrote "Implied" all over the place, and calculation is useful for many things that you probably don't know about.

[chrismunney]

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