PDA

View Full Version : Coupled Horses/Scratches for Odds Line Makers


pmd62ndst
12-18-2003, 02:42 AM
For those who try to make their own odds line, just wondering how you handle coupled horses.

Let's take a theoretical race where Horse 1 has a 30% chance while Horse 1A has a 10%. That would mean betting on 1 would have a 40% of winning.

Still, the scratching of one of those coupled horses is so frequent that you would almost have to make odds lines for each scenario. I've always avoided a coupled horse I like in a Pick 3/4/6 wager, just because I've been burned by picking a coupled horse that's been scratched and I've been left with Mr. NotSoFast.

While we are at it, do you adjust your odds line for scratches as well? My computer program I wrote gives me an odds line but I was just too lazy to do a recomputation after my contender(s) scratch. I've always just skipped those races but now I want to play them.

Any insight into this would be helpful.

PMD

Dave Schwartz
12-18-2003, 04:22 AM
My experience is that, except for high-class races, it is the weaker half of the entry that generally wins. Therefore, I toss the stronger entry and use the probability on the weaker animal.


Regards,
Dave Schwartz

sjk
12-18-2003, 05:43 AM
Most of my bets are at the computer which contains the odds lines and the program which created them. I identify the scratches wg\hen I get them. The computer then recreates the pace expectation without the scratched horses. It then assigns odds of 999-1 to all scrached horses and renormalizes the remaining odds line.

In the case of an entry, all their probabilities are summed; if one is scratched, his part of the sum is is replaced with .001 which is as good as using only the remaining runner.

David McKenzie
12-18-2003, 10:59 AM
Originally posted by pmd62ndst
For those who try to make their own odds line, just wondering how you handle coupled horses...

...While we are at it, do you adjust your odds line for scratches as well?

pmd,

That's an excellent question. How do you adjust your Betting Line for coupled entries?

I've used approaches glommed from Dr.Z, Barry Meadow and Dave Schwartz as well as some screwball adjustments of my own creation.

None of these applications have left me with a warm, fuzzy feeling.

Currently I'm using the better part of the entry, but that may change tomorrow. Heaven knows, I've flip-flopped back and forth a number of times.

Your second question is much easier to answer. Yes, I adjust the Betting Line for scratches.

The toughest question for me is whether or not to adjust the Betting Line by public opinion. And if so, by how much? I torture myself with this riddle constantly.

JustMissed
12-18-2003, 01:06 PM
sjk,

Do you assign odds to all horses or just your contenders?

JustMissed

sjk
12-18-2003, 01:15 PM
JM,

I make odds on all the horses. Strictly speaking, my computer makes odds on all the horses. I am just a bystander.


Dave S.,

I hope you are joking with us on this. I looked at entries in about 3000 races over the last 1 1/2 years; I left out races where I didn't think either horse had at least a 10% chance to win. I found the horse which looked like it had the best chance going into the race (you will have to trust me on this) had almost exactly twice the win percentage as the the one which looked like it had the lesser chance.

It seems to me that over the long run, horses that look better perform better whether they are part of an entry or not.

Dave Schwartz
12-18-2003, 03:48 PM
I am not joking. It is a phenomenon that I have "observed" for years.

This is not the case in higher class races (i.e. handicaps, stakes, etc.)


Dave

highnote
12-18-2003, 04:18 PM
Check out Betfair.com - you don't need an account to see the betting action. They don't couple horses even if they are coupled in the U.S. It might give you some idea of what the horses' odds might be if they were uncoupled in the regular tote.

shots
12-18-2003, 04:29 PM
Originally posted by Dave Schwartz
My experience is that, except for high-class races, it is the weaker half of the entry that generally wins. Therefore, I toss the stronger entry and use the probability on the weaker animal.


Regards,
Dave Schwartz

Ditto for uncoupled entries by the same trainer, high odds finish ahead of low odds horse.

Valuist
12-18-2003, 04:36 PM
Definitely true in uncoupled races. And its not just limited to bottom level claimers. Thunder Gulch and Real Quiet were examples of decent to big priced winners who were part of uncoupled entries that won the Kentucky Derby.

Hosshead
12-18-2003, 10:11 PM
I remember reading a study one time that said (statistically speaking), Entrys are bet down to smaller odds than they should go off at. Because the public believes it's a "great deal".

BMeadow
12-19-2003, 02:17 PM
Dave is either joking or terribly misinformed. I hope he's joking.

In Meadow's Racing Monthly, we ran a survey of 1,661 races in which a trainer entered two horses that were uncoupled due to different ownerships. The results:

In 589 races (35.5%), both finished out of the money.

In 722 races (43.5%), the shorter-priced horse finished in the money and ahead of the longer-priced horse.

In 350 races (21.0%), the longer-priced horse finished in the money and ahead of the shorter-priced horse.

Betting $2 from each group:

Shorter priced lost 16.7%
Longer priced lost 23.2%