Best Exacta Startegy ?

[Mr Saratoga]

Please don't lose sight of the fact that if you are playing where they show both exacta, and quinella payoffs, quite often the quinella is a better value.

[TrifectaMike]

Originally Posted by jfdinneen

TrifectaMike,

I endorse your approach (using matrix solution to set of simultaneous linear equations). In Excel,B is {=MMULT(MINVERSE(A),P)}.

Perhaps, you would outline a worked example for clarity.

John

Let's consider 4 exactas:

exacta_1 odds 7-1
exacta_2 odds 20-1
exacta_3 odds 14-1
exacta_4 odds 58-1

and we would like to acquire the following profit:

exacta_1 wins $100
exacta_2 wins $40
exacta_3 wins $100
exacta_4 wins $200

The question is, how much do we bet on each exacta?

We can write the system of linear equations as follows:

7b1 - b2 - b3 - b4 = $100
-b1 +20b2 - b3 - b4 = $40
-b1 -b2 +14 b3 -b4 =$100
-b1 -b2 - b3 +58b4 =$100

If you use Excel, it's rather easy to set up (I am assuming you are famil;iar with array formulas. I can see that you are in your question).

1. Enter the coefficent matrix in a nxn range
2. Enter the vector of profits in n-tall column
3. Select a blank n-tall column (This will be your solution. The bet amounts)
4. Type = MMULT(MINVERSE(coefficents matrix range),profits vector range)

Setting up the coefficients matrix is easier than it appears. The odds are always along the diagonal and all off diagonal elements are -1.

Also, this is not limited to like kind bets. You can include a wiin bet or two. Actually any combination of bets as long as you have the odds,

In the above example the computed bets are:

exacta_1 $16.61
exacta_2 $ 3.47
exacta_3 $ 8.86
exacta_4 $ 3.95

Obviously the bets have to rounded up or down to bettable amounts.

Mike

[pandy]

It was in one of the other races on the Jug card. But there are a lot of examples of this, solid favorites going off a true odds but lower than our "personal odds line."

[pandy]

Good point. In the old handicapping books, exotics, or exactas were said to be sucker bets. I never could understand that theory, it is nonsense.

[PaceAdvantage]

Originally Posted by xfile

This chart might be helpful to someone on the topic of overlay exactas. You will need to use an oddsline with it:
http://www.fullcardreports.com/CAP/o_e_c.asp

If you're going to use Barry Meadow's Exacta Overlay Prices chart, you really should credit him...your chart has the same exact numbers as the one in his landmark 1988 book Money Secrets At The Racetrack.

[teddy]

I have looked at the chart a few times... winner true odds? is that off odds. tote odds? Personally the underlaid combinations are those that are getting pounded because they make more sense due to racing style. So how can win odds have anything to do with a horses chance of running second. Two speeds may be runnning high figs on lone leads and terrible figs when they dont make the lead. Surely they are being bet to win based on that. I would prefer to rank them by win odds and amount bet to place. Just a thought.

[Aerocraft67]

Originally Posted by teddy

the underlaid combinations are those that are getting pounded because they make more sense due to racing style. So how can win odds have anything to do with a horses chance of running second.

I guess the hope is that a significant portion of the exacta pool is selecting contenders on overall ability to perform well and wheeling and boxing accordingly, which would leave contenders that are more likely to place than they are to finish elsewhere somewhat overlaid underneath, particularly if they're not among the lowest odds horses in the win pool. So a low-odds speed survivor winning over a closer for place that was ranked fifth in the win pool might not pay as much as it "should," given the clever use of the fifth win favorite for place while eliminating three of the other four top win prospects, but it might pay O.K. since more money will be focused on the top four contenders regardless of their likelihood to place. That said, a win contender holding on for place is not entirely unreasonable, particularly for close finishes. So the key there is to refine the pace handicapping.

Another thought is that you can use an exacta as a refined place bet. Say you like that high odds closer to finish in the money but figure one of the speeds will win, so you wheel your closer under a few likely winners. I freely admit that I generally can't muster the discipline to make this play without also using the key on top, adding a token win bet, or extending the wager to a trifecta to catch my "underneath key" in show. But it gets to your point about focusing on place contenders. The question is, is this kind of wagering predominant enough in the exacta pool to make truly logical place contenders underlaid?

[sammy the sage]

Originally Posted by xfile

Overlay key horse going off at 8-1 or higher on top with ALL underneath. Frequently catch some big exactas.

Yep, those happen EVERY day at EVERY race track...

and you've posted HOW many PRIOR to an actual race running

how about just an 8/1 winner...you're awful good on those shipper's..AFTER the fact!

and I can't do it either...or else I would

[RaceBookJoe]

Originally Posted by pandy

It was in one of the other races on the Jug card. But there are a lot of examples of this, solid favorites going off a true odds but lower than our "personal odds line."

Anytime you can take an even money favorite and turn him into 3-1 or higher, to me thats a good thing...just as long as the solid favorite actually is a solid favorite. rbj

[jfdinneen]

Mike,

As you already know...

In line with Arrow-Debreu State Preference Theory, a bet is a special kind of state contingent claim (contract paying differing amounts under different states of world). An outcome (state of world) is a specification of the values of all variables over the relevant time horizon (finish position of all horses in specific race). For example, in a three horse race (A,B,C), there are only six outcomes (ABC, ACB, BAC, BCA, CAB, CBA). An event is a collection of one of more outcomes (result of race) and all bets are on events. If an outcome is part of an event, then the bet on that event pays off, otherwise it pays nothing. All bets are represented as payoff vectors with one element for each state of the world. This notion of payoff vectors is central to the theory of complete markets (non-redundant set of bets). Also, a bet is redundant if its payoffs in every outcome can be duplicated by synthesizing some combination of the other available bets. Every portfolio of bets is a system of linear equations in some unknowns (investment amounts). Furthermore, some collection of the available bets must have payoff vectors that are linearly independent...

In that context, using my simplistic example above, if you believe A to be an overlay are you able to derive (using linear algebra) a portfolio of bets (wps, exotics) to maximize your advantage? Or, to put it another way, is it your experience that parimutuel markets are complete despite the lack of an option to sell short?

John

[TrifectaMike]

Originally Posted by jfdinneen

Mike,

As you already know...

In line with Arrow-Debreu State Preference Theory, a bet is a special kind of state contingent claim (contract paying differing amounts under different states of world). An outcome (state of world) is a specification of the values of all variables over the relevant time horizon (finish position of all horses in specific race). For example, in a three horse race (A,B,C), there are only six outcomes (ABC, ACB, BAC, BCA, CAB, CBA). An event is a collection of one of more outcomes (result of race) and all bets are on events. If an outcome is part of an event, then the bet on that event pays off, otherwise it pays nothing. All bets are represented as payoff vectors with one element for each state of the world. This notion of payoff vectors is central to the theory of complete markets (non-redundant set of bets). Also, a bet is redundant if its payoffs in every outcome can be duplicated by synthesizing some combination of the other available bets. Every portfolio of bets is a system of linear equations in some unknowns (investment amounts). Furthermore, some collection of the available bets must have payoff vectors that are linearly independent...

In that context, using my simplistic example above, if you believe A to be an overlay are you able to derive (using linear algebra) a portfolio of bets (wps, exotics) to maximize your advantage? Or, to put it another way, is it your experience that parimutuel markets are complete despite the lack of an option to sell short?




John

A complete market is perfectably hedgeable. In a probabilistic view there exist a unique Martingale measure for a complete market. There exists n wagers with known linearly independent payoff vector and known values. These n wagers form the basis for the n-dimensional space. For example, the lottery is a complete market, since every possible outcome is available for purchase.

And yes, you can derive a portfolio of wagers to maximize your advantage on a per event (race basis)., if at a minimum one overlay exists.

Mike

[Actor]

Originally Posted by jfdinneen

Mike,

As you already know...

In line with Arrow-Debreu State Preference Theory, a bet is a special kind of state contingent claim (contract paying differing amounts under different states of world). An outcome (state of world) is a specification of the values of all variables over the relevant time horizon (finish position of all horses in specific race). For example, in a three horse race (A,B,C), there are only six outcomes (ABC, ACB, BAC, BCA, CAB, CBA). An event is a collection of one of more outcomes (result of race) and all bets are on events. If an outcome is part of an event, then the bet on that event pays off, otherwise it pays nothing. All bets are represented as payoff vectors with one element for each state of the world. This notion of payoff vectors is central to the theory of complete markets (non-redundant set of bets). Also, a bet is redundant if its payoffs in every outcome can be duplicated by synthesizing some combination of the other available bets. Every portfolio of bets is a system of linear equations in some unknowns (investment amounts). Furthermore, some collection of the available bets must have payoff vectors that are linearly independent...

In that context, using my simplistic example above, if you believe A to be an overlay are you able to derive (using linear algebra) a portfolio of bets (wps, exotics) to maximize your advantage? Or, to put it another way, is it your experience that parimutuel markets are complete despite the lack of an option to sell short?

John

I love it!

[Actor]

Originally Posted by jfdinneen

...lack of an option to sell short?

Would not dutching every horse except the favorite be the equivalent of a short sale? I.e., you are betting that that particular horse will lose.

[markgoldie]

A couple of comments about this discussion.

First, exacta overlay charts. They are essentially useless. Why? Because the determination as to whether an exacta is an overlay or not is based on the win odds of the horses involved. Since the win odds at most tracks change drastically at the last minute, the determination of an overlay in the exacta pool is generally not possible with enough time to react in the form of a wager. That is, the basis for considerating an exacta overlaid may change dramatically when the price of the top horse (for example) goes up a point or more at the last second (or even after the race has begun). Similarly, the last minute exacta punches are also coming in very late which makes the certainty of an overlay very difficult.

In fact, the layout of the exacta probables is an excellent barometer of how the final win odds will settle. Since this is true, about all these exacta probables are good for is helping you determine if the late money was "inside" in the sense that it went contrary to the exacta-table's determination of price-value.

Next. As I have said many times, the larger the potential outcomes in a given pool, the more it is skewed toward favored combinations. I won't go over this again, because by now this statement should be settled law. Therefore, if you are planning on using a favorite in the exacta, you are actually better off just playing the horse to win and forgetting gimmicks altogether. Why??

Because any rational assessment that leads to playing a favorite must be based on a determination of value. That is, even though the horse will be favored, you have reason to believe that his closing price will be higher than it should be. Since wagering-pool inefficiencies are difficult to find in the first place (keeping in mind that we are fighting an onerous takeout), by playing the horse in gimmicks, you are combining the favorite with (most probably) underlaid animals. This combination of a skewed pool and the combination of your (hopefully) overlaid horse with underlaid animals is deadly over the long haul. Furthermore, dutching these probables does absolutely nothing to mitigate their essential lack of value.

[teddy]

so if your exacta price is the same as the chart, then do you bet? or is that what it is expected to pay...