odds line - Horse Racing Forum - PaceAdvantage.Com

Capper Al · 08-25-2014, 03:41 PM

My system uses elimination rules, therefore, some horses are not to win while others are not even in the money horses. These would receive odds of NA (not acceptable at any price). Oddsline get tossed around a lot in the forum. If an odds line doesn't show an empty set for some horses then to me it is of little use. The reasoning is that it doesn't separate contenders from non-contenders other than by price which isn't valid for all entries. This is vital to being profitable and choosing your wagers wisely.

Overlay · 08-25-2014, 06:25 PM

I assign odds to each horse, but that doesn't mean that I consider them all "contenders" in the usual sense of the word. If I had to draw a contender/non-contender line, it would be according to whether my assigned fair odds on a horse (not the horse's actual odds) are below or above the horse's random probability of winning based on the field size of the race. However, I don't discard or eliminate any horse totally from consideration out-of-hand. I want to make sure that I maintain visibility of each horse's chances, and my reasoning for those chances. That helps me both to keep longshots visible on my radar screen for possible (not necessarily mandatory) wagers, and also to analyze cases where my assessments turn out to be incorrect to a greater degree than can be accounted for by random variation.

thaskalos · 08-25-2014, 06:26 PM

Quote:

Originally Posted by Capper Al

My system uses elimination rules, therefore, some horses are not to win while others are not even in the money horses. These would receive odds of NA (not acceptable at any price). Oddsline get tossed around a lot in the forum. If an odds line doesn't show an empty set for some horses then to me it is of little use. The reasoning is that it doesn't separate contenders from non-contenders other than by price which isn't valid for all entries. This is vital to being profitable and choosing your wagers wisely.

If your system shows an "empty set" for some horses...doesn't this inflate the odds on the OTHER horses in the race? Where is the advantage in having your system eliminate certain horses right off the bat?

I would rather have a system that assigns odds to every horse in the race. No one is twisting my arm to bet a 50-1 shot, just because my line says it should be 25-1.

TJDave · 08-25-2014, 07:28 PM

Quote:

Originally Posted by thaskalos

If your system shows an "empty set" for some horses...doesn't this inflate the odds on the OTHER horses in the race?

Why?

What if you could eliminate all but two contenders?

thaskalos · 08-25-2014, 07:40 PM

Quote:

Originally Posted by TJDave

Why?

What if you could eliminate all but two contenders?

Theoretically...ALL entrants have at least SOME chance to win. Eliminating all but two of the horses from the very start is bound to exaggerate the odds of the two remaining horses...no?

Overlay · 08-25-2014, 07:51 PM

Quote:

Originally Posted by thaskalos

If your system shows an "empty set" for some horses...doesn't this inflate the odds on the OTHER horses in the race? Where is the advantage in having your system eliminate certain horses right off the bat?

I would rather have a system that assigns odds to every horse in the race. No one is twisting my arm to bet a 50-1 shot, just because my line says it should be 25-1.

Quote:

Originally Posted by thaskalos

Theoretically...ALL entrants have at least SOME chance to win. Eliminating all but two of the horses from the very start is bound to exaggerate the odds of the two remaining horses...no?

If you gave one or more horses in a race a zero chance of winning, wouldn't the 100% overall chance of there being a winner then be divided among fewer horses, which would increase their individual chances of winning, and correspondingly lower (rather than inflate or exaggerate/increase) their fair odds?

For example, in a five-horse field, each horse would have a random 20% chance of winning (fair odds of 4-1). If you were to determine that one of those horses in fact had a zero percent chance of winning, each of the remaining four horses would now have a 25% probability of winning, or fair odds of 3-1.

Or did you mean that assigning a zero percent chance of winning to one or more horses would inflate each remaining horse's percentage chance of winning, rather than its odds?

TJDave · 08-25-2014, 08:00 PM

Quote:

Originally Posted by Overlay

If you gave one or more horses in a race a zero chance of winning, wouldn't the 100% overall chance of there being a winner then be divided among fewer horses, which would increase their individual chances of winning, and correspondingly lower (rather than inflate or exaggerate/increase) their fair odds?

This.

Eliminate all but two and each has a 2-to-1 shot fair odds.

thaskalos · 08-25-2014, 08:05 PM

Quote:

Originally Posted by Overlay

If you gave one or more horses in a race a zero chance of winning, wouldn't the 100% overall chance of there being a winner then be divided among fewer horses, which would increase their individual chances of winning, and correspondingly lower (rather than inflate or exaggerate/increase) their fair odds?

For example, in a five-horse field, each horse would have a random 20% chance of winning (fair odds of 4-1). If you were to determine that one of those horses in fact had a zero percent chance of winning, each of the remaining four horses would now have a 25% probability of winning, or fair odds of 3-1.

Or did you mean that assigning a zero percent chance of winning to one or more horses would inflate each remaining horse's percentage chance of winning, rather than its odds?

Yes...this is what I meant to say. Eliminating all but two of the horses in a race would exaggerate the winning probabilities of the remaining duo.

TJDave · 08-25-2014, 08:08 PM

At the risk of answering for Capper Al:

Eliminating is exactly that. They ain't there.

At least, that's how I figure it.

thaskalos · 08-25-2014, 08:09 PM

Quote:

Originally Posted by TJDave

At the risk of answering for Capper Al:

Eliminating is exactly that. They ain't there.

At least, that's how I figure it.

Can you list an elimination rule which would neatly eliminate a horse as if it weren't there?

thaskalos · 08-25-2014, 08:14 PM

Quote:

Originally Posted by TJDave

This.

Eliminate all but two and each has a 2-to-1 shot fair odds.

How often would you expect to be right when you reduce the field down to 2 horses?

TJDave · 08-25-2014, 08:18 PM

Quote:

Originally Posted by thaskalos

Can you list an elimination rule which would neatly eliminate a horse as if it weren't there?

Not specifically as my methodology isn't rigid. But it happens every race I bet...or I don't. If, IMO, a horse can't light the board then he is eliminated.

TJDave · 08-25-2014, 08:20 PM

Quote:

Originally Posted by thaskalos

How often would you expect to be right when you reduce the field down to 2 horses?

As often as that happens...

Which isn't very.

Overlay · 08-25-2014, 10:59 PM

Quote:

Originally Posted by TJDave

This.

Eliminate all but two and each has a 2-to-1 shot fair odds.

If you eliminate all but two horses from consideration, and you believe that each of the two has an equal chance to win, wouldn't the fair odds on each of them be even money (1-1), rather than 2-1?

thaskalos · 08-25-2014, 11:16 PM

Quote:

Originally Posted by Overlay

If you eliminate all but two horses from consideration, and you believe that each of the two has an equal chance to win, wouldn't the fair odds on each of them be even money (1-1), rather than 2-1?

To assign odds of even money on them would mean that you expect this duo to prevail in this scenario 100% of the time.