Questions About Trifectas and Supers

[HalvOnHorseracing]

Originally Posted by Franco Santiago

Seriously, people handicap much more loosely for the show spot and they toss in all kinds of crap. They ain't tossing one out based on AI...now they might toss one IN based in AI, but it won't be because of some value algorithm...it'll be because they want to HIT THE BET.

I've opined in the past that people have been trained to select the winner, but they have not been trained to accurately evaluate any other finish position. So if you followed the exacta probability discussion, second place is simply an extension of the win odds, with the assumption that the second best horse has the highest probability of finishing second, the third best third, and so on. Of course, this is not always true. "Sucker" horses (or horses with seconditis) may have a 2% chance of winning and a 50% chance of finishing second, and an exacta system based on win probability might underestimate this horse. The other issue is that as you place horses in slots below win, their win odds become less and less valuable as a predictor. Which is why longshots regularly occupy the backholes, and people use "all kinds of crap" in the third and fourth slots. I actually did some graphs of different types of runners (high win probability, low win probability, mid-level probability, in-the-money type, all or nothing type) and suggested even the low win types had probabilities of finishing third or fourth much higher than the win probability, and you had to draw the line farther down the list of starters than you might just based on win odds.

[thaskalos]

Originally Posted by HalvOnHorseracing

I've opined in the past that people have been trained to select the winner, but they have not been trained to accurately evaluate any other finish position. So if you followed the exacta probability discussion, second place is simply an extension of the win odds, with the assumption that the second best horse has the highest probability of finishing second, the third best third, and so on. Of course, this is not always true. "Sucker" horses (or horses with seconditis) may have a 2% chance of winning and a 50% chance of finishing second, and an exacta system based on win probability might underestimate this horse. The other issue is that as you place horses in slots below win, their win odds become less and less valuable as a predictor. Which is why longshots regularly occupy the backholes, and people use "all kinds of crap" in the third and fourth slots. I actually did some graphs of different types of runners (high win probability, low win probability, mid-level probability, in-the-money type, all or nothing type) and suggested even the low win types had probabilities of finishing third or fourth much higher than the win probability, and you had to draw the line farther down the list of starters than you might just based on win odds.

IMO...the second-best horse will NOT finish second if it shares the same running style as the race's BEST horse.

[ReplayRandall]

Originally Posted by thaskalos

IMO...the second-best horse will NOT finish second if it shares the same running style as the race's BEST horse.

What crappy book did you read that from??....I got two authors in mind, who might even post here at PA.

[DeltaLover]

Originally Posted by thaskalos

IMO...the second-best horse will NOT finish second if it shares the same running style as the race's BEST horse.

Whether this is true or false will be shown by the related data.

How the data are presented to the decision algorithm is where the real challenge lies while the deepness of the machine learning is of a secondary importance, in the sense that it is relatively easy to switch network topologies and rely on a trial and error process which although it might become time consuming it can still be automated and run automatically in the background.

This thread is representative of the most interesting topic that I can think about horse betting but it is not presented in a sufficiently detailed level that can allow for concrete conversations and exchange of ideas and methodologies. I feel that to proceed in a right direction we certainly need training and testing data otherwise the thread will become another "opinion battlefield" as usually.

[HalvOnHorseracing]

Originally Posted by thaskalos

IMO...the second-best horse will NOT finish second if it shares the same running style as the race's BEST horse.

It was an assumption made for the purposes of calculation using a generic example with no handicapping consideration. Clearly in the real world you don't ignore handicapping.

[HalvOnHorseracing]

Originally Posted by DeltaLover

Whether this is true or false will be shown by the related data.

How the data are presented to the decision algorithm is where the real challenge lies while the deepness of the machine learning is of a secondary importance, in the sense that it is relatively easy to switch network topologies and rely on a trial and error process which although it might become time consuming it can still be automated and run automatically in the background.

This thread is representative of the most interesting topic that I can think about horse betting but it is not presented in a sufficiently detailed level that can allow for concrete conversations and exchange of ideas and methodologies. I feel that to proceed in a right direction we certainly need training and testing data otherwise the thread will become another "opinion battlefield" as usually.

The theory behind calculating fair pay on the exacta is sound enough. You handicap the probabilities of each respective horse finishing first. The tricky part is making a calculation for the probability of any respective horse finishing second. Simplistically you can adjust the place odds after putting a horse in the win slot by redistributing the percentage from the win horse and redistributing it to the remaining runners.

Obviously that is a formulaic method with no handicapping beyond the win hole.

After putting a respective horse in first, you can also readjust the place percentages by rehandicapping the race. That is a subset of Thask's point. When Horse A finishes first, that may compromise the probability of Horse B finishing second. But you might also argue that you took that into account when you handicapped Horse A on top, in which case Horse B wouldn't have been the second best horse in the first place.

If I'm writing for the average horseplayer, I'm going to provide an easy to use method that is sustainable. I think that is

(win probability * place probability) = exacta probability (converted to odds)

exacta odds + margin of safety = acceptable exacta pay

A valuable discussion would be how to calculate win and place odds, because the rest of it is mechanical.

And I'd argue that once you have a useful exacta price, you can extrapolate that to trifectas and supers.

[DeltaLover]

Originally Posted by HalvOnHorseracing

The theory behind calculating fair pay on the exacta is sound enough. You handicap the probabilities of each respective horse finishing first. The tricky part is making a calculation for the probability of any respective horse finishing second. Simplistically you can adjust the place odds after putting a horse in the win slot by redistributing the percentage from the win horse and redistributing it to the remaining runners.

Obviously that is a formulaic method with no handicapping beyond the win hole.

After putting a respective horse in first, you can also readjust the place percentages by rehandicapping the race. That is a subset of Thask's point. When Horse A finishes first, that may compromise the probability of Horse B finishing second. But you might also argue that you took that into account when you handicapped Horse A on top, in which case Horse B wouldn't have been the second best horse in the first place.

If I'm writing for the average horseplayer, I'm going to provide an easy to use method that is sustainable. I think that is

(win probability * place probability) = exacta probability (converted to odds)

exacta odds + margin of safety = acceptable exacta pay

A valuable discussion would be how to calculate win and place odds, because the rest of it is mechanical.

And I'd argue that once you have a useful exacta price, you can extrapolate that to trifectas and supers.

The objective is not to discover the winning probabilities but the error that is embedded in the crowd’s betting.

The winning probability of a horse is not only useless for betting purposes (since we are not betting into fixed lines) but, given the chaotic nature of the game it is also impossible to calculate with the necessary accuracy. We might end up with a valid way to order the horses based in their winning probabilities (similar to the behavior of the final odds as formed by the crowd) but such a model will not spawn precise enough numbers to allow for successful betting (which again is getting worse given the fact that you never know in advance your expected payout).

What is possible though, is to build a probability distribution expressing the accuracy of the crowd in a cumulative way. Having this kind of information available it is valid to expect that your potential advantage (of disadvantage if the crowd will prove your model wrong) to materialize after a relative long sequence of races. In other words and to paraphrase a common saying: “You can beat the races but you cannot beat the race:

[thaskalos]

Originally Posted by DeltaLover

The objective is not to discover the winning probabilities but the error that is embedded in the crowd’s betting.

The winning probability of a horse is not only useless for betting purposes (since we are not betting into fixed lines) but, given the chaotic nature of the game it is also impossible to calculate with the necessary accuracy. We might end up with a valid way to order the horses based in their winning probabilities (similar to the behavior of the final odds as formed by the crowd) but such a model will not spawn precise enough numbers to allow for successful betting (which again is getting worse given the fact that you never know in advance your expected payout).

What is possible though, is to build a probability distribution expressing the accuracy of the crowd in a cumulative way. Having this kind of information available it is valid to expect that your potential advantage (of disadvantage if the crowd will prove your model wrong) to materialize after a relative long sequence of races. In other words and to paraphrase a common saying: “You can beat the races but you cannot beat the race:

Yes...but is the crowd exhibiting the same wagering "characteristics" across different time periods...or does the crowd "get smarter" as time goes on...thus gradually negating whatever "advantage" we might think we have over the game? If it is indeed "getting tougher to win in this game", as most of us seem to think, then the assumption must be made that any predetermined advantage that we might currently have can hardly be used as an "expectation" of things to come.

[traynor]

Originally Posted by DeltaLover

The objective is not to discover the winning probabilities but the error that is embedded in the crowd’s betting.

The winning probability of a horse is not only useless for betting purposes (since we are not betting into fixed lines) but, given the chaotic nature of the game it is also impossible to calculate with the necessary accuracy. We might end up with a valid way to order the horses based in their winning probabilities (similar to the behavior of the final odds as formed by the crowd) but such a model will not spawn precise enough numbers to allow for successful betting (which again is getting worse given the fact that you never know in advance your expected payout).

What is possible though, is to build a probability distribution expressing the accuracy of the crowd in a cumulative way. Having this kind of information available it is valid to expect that your potential advantage (of disadvantage if the crowd will prove your model wrong) to materialize after a relative long sequence of races. In other words and to paraphrase a common saying: “You can beat the races but you cannot beat the race:

Exactly. The probability of a horse winning--if only calculated as a factor of particular attributes of that individual horse--is, at best, no more than a rough approximation. To be accurate enough to be worth betting on, it would have to be the result of calculating that individual horse's win probability as a factor of the combined attributes of this specific mix of horses in this specific race. And even then would still be only an approximation.

You did a really good job of explaining your perspective in another thread a few days ago, and I am finally beginning to understand what you have been writing all along.

Specifically (as you point out above) the useful thing is not necessarily the win probability (or place probability, or whatever probability), but what the other bettors believe those probabilities to be.

That makes the study of combinations of attributes in that specific group of horses more useful than study of the individual horses' attributes as predictors. A simplistic example would be trifecta/superfecta wagers "automatically" including class droppers, or some other favored attribute. Many of the inclusions (in particular those based on what some believe to be "pace analysis" and "preferred running styles") have little or nothing to do with the actual value of that particular attribute of that particular horse in that particular race.

To clarify, " the study of combinations of attributes in that specific group of horses," consider a race with two near-equal front runners. Bettors may (as a mindless knee-jerk reflex based on spurious premises) believe an "early speed duel" will "burn out" both front runners, and "set the race up for a strong closer"--and bet accordingly.

My understanding of what you are writing (which may be totally wrong, and if so, I apologize) is that you believe it is more useful (or at least as useful) to study what the bettors are likely to do as a result of seeing certain attributes/factors in a given group of horses as a predictor than to study (only) the certain attributes/factors as predictors.

And that knowledge is best derived (and perhaps can ONLY be derived) from studying trends and patterns in large groups of races, rather than trying to divine the future based on the few races of which one has "personal experience."

[AndyC]

Originally Posted by DeltaLover

The objective is not to discover the winning probabilities but the error that is embedded in the crowd’s betting.

Without the winning probabilities how would someone know if the public is making an error?

[thaskalos]

Originally Posted by traynor

Exactly. The probability of a horse winning--if only calculated as a factor of particular attributes of that individual horse--is, at best, no more than a rough approximation. To be accurate enough to be worth betting on, it would have to be the result of calculating that individual horse's win probability as a factor of the combined attributes of this specific mix of horses in this specific race. And even then would still be only an approximation.

You did a really good job of explaining your perspective in another thread a few days ago, and I am finally beginning to understand what you have been writing all along.

Specifically (as you point out above) the useful thing is not necessarily the win probability (or place probability, or whatever probability), but what the other bettors believe those probabilities to be.

That makes the study of combinations of attributes in that specific group of horses more useful than study of the individual horses' attributes as predictors. A simplistic example would be trifecta/superfecta wagers "automatically" including class droppers, or some other favored attribute. Many of the inclusions (in particular those based on what some believe to be "pace analysis" and "preferred running styles") have little or nothing to do with the actual value of that particular attribute of that particular horse in that particular race.

To clarify, " the study of combinations of attributes in that specific group of horses," consider a race with two near-equal front runners. Bettors may (as a mindless knee-jerk reflex based on spurious premises) believe an "early speed duel" will "burn out" both front runners, and "set the race up for a strong closer"--and bet accordingly.

My understanding of what you are writing (which may be totally wrong, and if so, I apologize) is that you believe it is more useful (or at least as useful) to study what the bettors are likely to do as a result of seeing certain attributes/factors in a given group of horses as a predictor than to study (only) the certain attributes/factors as predictors.

And that knowledge is best derived (and perhaps can ONLY be derived) from studying trends and patterns in large groups of races, rather than trying to divine the future based on the few races of which one has "personal experience."

Has it been proven that these "studies of trends and patterns in large groups of races" have the PREDICTIVE effect that they pretend to have?

[traynor]

AI is interesting, but not magic. It can "learn" based on what it is fed. It can "project" based on what has happened in the past. Much the same as people do, but over more data, faster.

[Frost king]

Personally I find the Trifecta to be a bad bet. To me, it should pay out 10x or more than the exacta bet, and that does not happen to often. If you are going to spend $30-50 trying to catch a bottom horse, you are better off putting that same money into the exacta and trying to catch that. A perfect example was at GP with Uncle Runt. He paid $210.20 to win. The $2 exacta was $431.40, and the tri came back $1288.70. So it was only 3x the exacta. Check out the payouts, and the tri very rarely tops the exacta by 10x. So if you took all the time and money and played exactas, you would be further ahead, unless you have the uncanny ability to hit the thing straight up.

[traynor]

Originally Posted by thaskalos

Has it been proven that these "studies of trends and patterns in large groups of races" have the PREDICTIVE effect that they pretend to have?

Of course. Basic data mining processes and procedures. Training sets, control sets, data cleaning, tossing outliers. Not rocket science. Basic stuff, that almost everyone "studying" horse races avoids like the plague, while busily chasing rainbows that don't exist.

[thaskalos]

Originally Posted by Frost king

Personally I find the Trifecta to be a bad bet. To me, it should pay out 10x or more than the exacta bet, and that does not happen to often. If you are going to spend $30-50 trying to catch a bottom horse, you are better off putting that same money into the exacta and trying to catch that. A perfect example was at GP with Uncle Runt. He paid $210.20 to win. The $2 exacta was $431.40, and the tri came back $1288.70. So it was only 3x the exacta. Check out the payouts, and the tri very rarely tops the exacta by 10x. So if you took all the time and money and played exactas, you would be further ahead, unless you have the uncanny ability to hit the thing straight up.

Why should the trifecta always pay 10X more than the exacta? Does the exacta always pay 10X more than the win-bet?