Exacta Wagering

[MartyL]

Hi All:
Is there a formula available to quickly get the payoff for an exacta
whose odds are:
horse1 9/5
horse2 8/1
or just to see if an exacta bet is worth the trouble etc.?
regards
MartyL

[formula_2002]

The following s calculations are somewhat unconventional.

A horse adjusted expected win % = 1/((odds+1))*(1+edge)
B horse adjusted expected win % = 1/((odds+1))*(1+edge)

The expression (odds+1) is the final post time odds of the horse +1.

Calculate A and B then

Min exacta odds = 1/(A*(B/(1-A)))

Example; 6% edge on the horse and A -15% edge on the B horse.

Say;
A odds =2-1
B odds = 3-1

A adjusted win % = (1/((2+1))*(1+.06)= .35%
B adjusted win % = (1/((3+1))*(1-.15)= .21%

Min exacta odds = (1/(.35*(.21/(1-.35))))-1 = 7.84 to 1

The unconventional part is the use of the edge. Most books demonstrate the calculation using value of 1-(track-out) rather then your edge.
I use the win pool edge. Then I can compare the exacta edge to my win edge.

If the above returned an exacta mutual of $15, which is equivalent to 6.5-1, the exacta edge would be (6.5-7.84)/7.84
= an exacta edge of -17%

Now you can compare your win pool edge of the A horse, 6% , to the exacta pool edge -17% , and clearly see that in this example, the exacta play created a 283% loss to you win pool edge.

If you don’t know your win pool edges, substitute with the track take-out.

I’ll be adding an inter- active exacta table to my personal web page for your use.

The above does not take into account the volatility in horse racing odds.

Joe M

[PurplePower]

Originally posted by MartyL
Hi All:
Is there a formula available to quickly get the payoff for an exacta
whose odds are:
horse1 9/5
horse2 8/1
or just to see if an exacta bet is worth the trouble etc.?
regards
MartyL
Marty - as you can tell from Joe's post, the answer to your question is "No". Best way to get payoffs is to be at home on your computer using a service that has the exacta matrix available for viewing at any time. Or find a channel at your home track that is showing the matrix. (Fairgrounds used to show both exacta and quinella will pays on about 1 of 10 monitors. Don't know if they still do or not.)
Since the exacta pool is totally separate from the win pool, the exacta payoffs are mathmatically independent of the win odds. Since players generally bet the same horses in the exotic wagers as in the straight pools, the payoffs do generally follow the odds so an "estimate" is possible. Obviously using off-time odds is no help if you are wanting to determine whether to bet the exacta in this race - or a WIN bet - or pass.
One way when considering the favorite on top is to multiply the odds of your contenders and double the result. (In your example, 1,8 times 8 equals 14.4 times 2 equals $29.00). I wouldn't take that exacta risk unless the $2 exacta was paying over $30.00. Maybe not as "precise" as Joe's formula, but it will get you an answer a little quicker

[JustMissed]

Marty, I use this method and it has proved quick and fairly accurate:

Calcuate the win payoff of both horses.

Multiply 1/2 of A payoff by B payoff.

Your example:

Horse A-9-5=$5.60

Horse B-8-1=$18.00

Result 1/2 x $5.60 = $2.80 x $18.00 = $50.40 Estimated Exacta Payoff.

You might want to take some of the old charts for the tracks you play and spot check a few actual payoffs.

Like Purple said the monitor is the best but my method will work in a pinch.

Good luck,

JustMissed
:)

[MartyL]

Guys:
Appreciate the positive feed back.
Will try your suugestions!
Regards
MartyL

[Mr. Blonde]

Give this link a try.


http://www.a1handicapping.com/exacta.htm

[formula_2002]

Mr. B, nice site.

I checked a few exacta odds using my data base and compared them to the chart, and then used the normal exacta calculation based on 17% take-out and breakage in the win pool.



2-1 and 2-1 chart 8.35-1, my db 8.35-1 , calculation, 8.45-1

3-1 and 3-1 14.71-1 16.9-1 17.41-1

4-1 and 4-1 23.31-1 26.75-1 29.27-1

5-1 and 5-1 35.13-1 40-1 44-1


My data is based on over 10,000 east coast exacta races.
(I don't trust the west coast exacta payout in my data base, since some of the west coast tracks report their exacta payouts to $1 and I never made the adjustment.)

In view of the above, I would tend to go by the "calculated" exacta odds. They appear to be more conserative, and in the long run would work-out better.

One thing is for sure,, all three methods are trending in the same direction..

Joe M

[ceejay]

If you are looking for 15-20% overlays you might look at http://www.turfpedia.com/playing_the_races/exacta_betting.html
. So, you might take 80-85% of these as "fair value." Using this and your example, fair value would be $52-55.