beating no vig line, quick example

**LT Profits** · 08-01-12, 10:23 PM

69.874 / 30.126 = 2.3194

**LT Profits** · 08-01-12, 10:26 PM

Originally posted by thesoxman101

A few quick questions... Obviously if you bet either the -235 or +225 you would not be beating the no vig line correct?

One last question, is the no vig line always the same in terms of +/- because all the times I tried on his calculator gives just one number

Correct and Yes

**therushishere** · 08-02-12, 01:54 AM

This should help:

http://forum.sbrforum.com/handicapper-think-tank/11994-introduction-betting-lines-percentages.html

Good luck.

**MidnightToker** · 08-02-12, 07:43 AM

Originally posted by thesoxman101

Hi, so earlier there was a Houston vs. MIL game, and the closer for Pinnacle was +227 (Houston) / -244 (MIL)

I used MoneyF0ckers program and it says the no vig line is +/- 231.94.

-244 -> .7093
+227 -> .3058

= 101.5%

So the no vig implied probabilities are around 69.874% for the favorite, and 30.1% for the dog... Now how do you get that no vig line of +/- 231.94 from these percentages?

Did you come up with the no-vig cover probabilities on your own? If so, all you need now is a little algebra. Since the no-vig lines for favourite and dog are complementary (same number, one positive one negative), we can use either to calculate the no-vig line.

Let's do the dog. We know the formula for finding a dog's cover probability given the dog line:

100 / (100+dog line) = cover %

Substituting what we know and using x for the dog line we get:

100 / (100+x) = 0.301 -> 100 = 0.301 * (100+x) -> 100 = 30.1 + 0.301x -> (100 - 30.1) / 0.301 = x - > x = 232.226

Thus the fair no vig line is 232.226 (-232 for the favourite, +232 for the dog). The reason this isn't the same result as you got in the calculator is that your given no-vig cover % is not exactly right. You gave 30.1%, but the exact result is:

100/(100+227) / (100/(100+227) + 244/(100+244)) = 0.301258

If you use the full precision instead of approximating, we get:

100 / (100+x) = 0.301258 -> 100 = 0.301258 * (100+x) -> 100 = 30.1258 + 0.301258x-> (100 - 30.1258) / 0.301258 = x - > x = 231.941

Which is the number you got from the calculator.

For the favourite, just for kicks, we know -risk/(100-risk) = (244/(100+244)) / (100/(100+227) + 244/(100+244)) thus

-x/(100-x) = 0.698742 -> x = -0.698742 * (100-x) -> x = -69.8742 + 0.698742x -> 0.301258x = -69.8742 -> x = -69.8742/0.301258 -> x = -231.941

Hopefully this is thorough enough that you can see where everything comes from.

**thesoxman101** · 08-02-12, 11:34 AM

Thanks guys, intuitively why is the no vig line always the same -/+ (sorry if this is obvious) but the implied probability obviously isn't going to be.

**LT Profits** · 08-02-12, 11:52 AM

Originally posted by thesoxman101

Thanks guys, intuitively why is the no vig line always the same -/+ (sorry if this is obvious) but the implied probability obviously isn't going to be.

One team's implied probability is the exact reciprocal of the other, i.e. 51% vs. 49% or 52.5% vs. 47.5%.

**thesoxman101** · 08-02-12, 12:09 PM

I know, so why is the no vig line the same then? That is what I was confused about.

**LT Profits** · 08-02-12, 12:23 PM

It is basic algebra, it HAS to be as long as the percentages add up to 100. In simplest terms, let's say you know one team's odds of winning is 52% and, therefore, its opponents' is 48%. How do you convert that to a line? The computation is exactly the same both ways (52 / 48 = 1,083), except the 52% is -108.3 and the 48% is +108.3.

**thesoxman101** · 08-02-12, 12:27 PM

Thank you!

**MidnightToker** · 08-02-12, 01:26 PM

The line isn't actually the same, they're the complements to each other.

-150 = 150/250 = 60%
150 = 100/250 = 40%

Note that for two complementary lines, the denominator will always be the same since for the two different formulas (dog and favourite):

Dog: 100/(100 + dog line)
Favourite: -fav line / (100 - fav line)

Through basic algebra, we can reformulate the favourite line like so:

fav line / (fav line - 100)

We can multiply both terms here by -1 and since the fav line is always negative we get +fav line/(+fav line + 100). Now note both equations:

Dog: 100/(100 + dog line)
Fav: +fav line / (100 + +fav line)

Both of these equations represent the implied cover probability. No vig means they should add up to 100% total. We can see that the dog has 100 as numerator and the fav has a variable as numerator. In order for both to equal to 100% together, assuming a denominator of (100 + dog line), we'd have to have a favourite line like ((100+dog line) - 100) / (100 + dog line). You should be able to see from that that the dog line and the fav line have to be the same for that equation to work (since it reduces to dog line/100+dog line, which is the same equation as +fav line/100 + +favline.

Hope that was understandable. Not a math wiz by any means but that seems to work out.

**wrongturn** · 08-02-12, 02:12 PM

Originally posted by thesoxman101

I know, so why is the no vig line the same then? That is what I was confused about.

That is the beauty of American Odds. It was designed just for this purpose.

**LostBankroll** · 08-10-12, 04:16 AM

too much shit talk just fadde landers to a couple Million dollars a year...