Calculating Edge against Closing Lines

[dmolition]

Hi guys i was looking for a little help on something.

Im trying to keep track of my edge or EV+ on all my previous plays comparing my line against pinny's closing line, i use the half-point calculator for spread sports, but if i use NHL and MLB on MLs how do i get my edge?

For example, i had San Diego on MLB at +130 and it closed at +115 is a 15 cent edge over the closing line but how do i get a percentage% like the half point calculator does.

for example if on the NBA i got the bucks at -3.5 -101 and assuming the closing line is -4 -111 the Half point calculator shows my bet as having a 5.6% Edge over the closing line, now how do i get this percentage on Moneyline sports?.

Is my analysis correct? I assume we want to beat the closing line in most if not all of our bets, but does calculating our edge on average with every bet, help us find our real edge for kelly bets and whatnot, and also allows to see on bad runs if our expectation is still good on our bets on average?

Sorry for my grammar, english is not my first language.

Thanks for the help.

[dmolition]

I got the ML calculation with the odds converter, taking the no vig price of my bet.

Now what i am not sure if it is useful to make an average of your edge % on all bets and with a big enough sample size and use this % as an estimate of your edge for kelly betting.

Thanks.

[Pancho sanza]

Using your examples, calculate the win probability implied, -123/+115 = 45.7 % for the dog, which equates to +119 for zero edge.

Since you got +130, your edge was +9.2 % (130-119)/(119), and your roi at that edge would be +5.1 %

[Ganchrow]

i had San Diego on MLB at +130 and it closed at +115 is a 15 cent edge over the closing line but how do i get a percentage%

You got the line at , it closed at with (say) a 20¢ spread. (Obviously if the market on the closer were tighter than a 20¢ spread you'd use that.)

So at /, the zero-vig implied probability on the dog would be about:

/(+) ≈ 44.74%

A 44.74% win probability given payout odds of +130 then yields an edge of:

44.74%* - 1 ≈ 2.90%

See:

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

-and-

http://forum.sbrforum.com/handicapper-think-tank/12142-introduction-expectations-theoretical-hold.html

[MonkeyF0cker]

I'll use your example and clarify a bit. First, you need to know the price of the favorite on your Pinny closer. Since Pinny MLB lines are 8 cents at +115, the closer should have been -123/+115. Next, you have to calculate the no-vig probability of the Pinny closer. There are two steps to this.

First calculate the no-vig implied probabilities of the Pinny closer. To do this, you can use these formulas:

Favorite zero-vig implied probability
= P(f) = -F/(100-F)

Dog zero-vig implied probability
= P(d) = 100/(100+D)

This yields:

P(f) = -(-123)/[100-(-123)] = 123/223 ≈ 0.55156950672645739910313901345291
P(d) = 100/(100+115) = 100/215 ≈ 0.46511627906976744186046511627907

Next, you calculate the lineset probability. Since we want the dog probability, we use the bottom formula of the two choices below.

Line set favorite probability
      P(f)
= -----------
   P(f)+P(d)

Line set dog probability
     P(d)
= -----------
   P(f)+P(d)

The lineset probability is then: 0.46511627906976744186046511627907/(0.55156950672645739910313901345291 + 0.46511627906976744186046511627907) ≈ 0.45748281875064109139398912708996

Rounding, we get a zero-vig probability of 45.7483% for San Diego, according to the Pinny closer.

From there, you can calculate your edge by multiplying the zero-vig probability (in decimal form) of the closer by the payout multiplier of your wager and subtracting from 1. The payout is the total amount returned if the wager were to win. This includes your initial wager. Since (at +130) you would receive your initial wager plus 1.3 times your wager, your payout multiplier would be 2.3. So your edge on this wager would be:

(.457483 * 2.3) - 1 ≈ 5.22%

[dmolition]

Thanks for the great input guys, ill check my math and get back to you if i have further questions on ML.

Seeing this no vig calculations, those this means that on the spread sports that i have been using (NBA, NCAAB)the edge given on the Half point calculator is wrong or is the correct edge on my bets for purposes of tracking?

Thanks again.