Backfitting Deluxe for the Kentucky Derby

[Helles]

I am not waving this algorithm declaring I have found the one true way. I am still trying to wrap my mind around the fact that it successfully ranked low-priced as well as longshot winners in the top 2 or 3. That's the reason my post took the direction it did. I was originally looking to make a contribution by pointing out a few factors that some of you might not have considered that winners had in common.

Out of curiosity, I used this analyst to handicap the Oaks yesterday and this was the output:
8 I'M A CHATTERBOX
9 MONEY'SONCHARLOTTE
7 LOVELY MARIA
Result was 7,2,8

I know this means nothing in the big picture, but the result was interesting nonetheless.

[DeltaLover]

Originally Posted by Dexter C. Hinton

It is interesting how many individuals can only respond with:

a) Back Fitting (bah):

b) No statistical substance: (not enough data points, etc.)

For (a), the methodology you utilized of course was to determine, to your best ability, the correlated factors resulting from your analysis. It is easy to be critical and scream 'back fit'. I would rather give the benefit of the doubt, and say 'utilization of predictable elements'.

For (b), there will always be individuals who also scream, 'No statistical substance' because of limited sample size, etc. From a pure statistician's view that will always be true because we live is a world of limited data points (i.e., perhaps if you had detailed data back a hundred or so years, for this particular race, they may give you a break). I doubt it however, they would most likely tell you a 100+ data points is not enough for statistical relevance.

The interesting point of your post is that studying a specific track at a specific distance with a consistent level of participants (i.e., three (3) year olds, etc.), under ALL types of weather conditions, with what one can be said to be to many horses, utilizing a type of 'simple AI', you were able to legitimately test your algorithm against back races.

For the record, I do not put a lot of faith in 'black box handicapping'. However as old as I am, one thing I have learned is the game has changed. 'Dumb money' has become pretty much non-existent and wagers have to utilize all the resources in their toolbox. What you have articulated is one of those 'tools'.

This should not be criticized for what was done, but only questioned for its applicability to be useful in the future (in conjunction with the individual handicapping resources each one has).

As I am sure you are aware, it is much easier to criticize, combined with offering no legitimate ideas or alternatives.

Even if your findings do apply to this year, maybe next year also, and beyond, you can be rest assured that one year it will fail and the response you will get will be "What do you expect of back fitting, it had no statistical significance to begin with".

dch
05/02
10:37.31..31

Sorry, but what you are saying here is complete wrong and creates the wrong impression to people who try to handicap using a computer...

[Saratoga_Mike]

Originally Posted by DeltaLover

Sorry, but what you are saying here is complete wrong and creates the wrong impression to people who try to handicap using a computer...

What did you find most objectionable DL? I don't use a database, so I always like to hear from people who do - I think you do?

[DeltaLover]

Originally Posted by Saratoga_Mike

What did you find most objectionable DL? I don't use a database, so I always like to hear from people who do - I think you do?

Back-fitting is the number one reason for erroneous conclusions, especially when combined with small data

[garyoz]

Originally Posted by DeltaLover

Back-fitting is the number one reason for erroneous conclusions, especially when combined with small data

and highly correlated variables.

[Helles]

Originally Posted by whodoyoulike

... I hope you provide an update after the Derby is run (referencing this post #1). Let us know whether you made a wager and the type of wager(s) using your contenders.

Buoyed by the success of the analyst picking the Oaks, I did use the output to make some Derby wagers.

Here is that output again:
18 American Pharoah 39|
10 Firing Line 25|
21 Frammento 11|
8 Dortmund 8|

Result 18,10,8,15

I made win wagers on the top three in varied amounts. I made exacta bets with varying base amounts by boxing the top two, boxing the top three and wheeling the top three against the next nine highest ranked horses and finally a $1 exacta with Frammento/All, "just in case".

[TexasDolly]

Originally Posted by Helles

Buoyed by the success of the analyst picking the Oaks, I did use the output to make some Derby wagers.

Here is that output again:
18 American Pharoah 39|
10 Firing Line 25|
21 Frammento 11|
8 Dortmund 8|

Result 18,10,8,15

I made win wagers on the top three in varied amounts. I made exacta bets with varying base amounts by boxing the top two, boxing the top three and wheeling the top three against the next nine highest ranked horses and finally a $1 exacta with Frammento/All, "just in case".

I was glad to see your success with the analysis you made. I am growing weary of the backfitting arguments. I never have enough data that has any degree of consistency
to do any thing but backfit. Raybo has made the point a dozen times about his program which uses around 30 days of current data and he maintains that it works profitably and there are others I imagine. At any rate, I would be very pleased to be able to process 900 factors and find 48 that seemed to fit
various horses such as you describe.
Congratulations to you on your work.
TD

[Saratoga_Mike]

Originally Posted by Helles

Buoyed by the success of the analyst picking the Oaks, I did use the output to make some Derby wagers.

Here is that output again:
18 American Pharoah 39|
10 Firing Line 25|
21 Frammento 11|
8 Dortmund 8|

Result 18,10,8,15

I made win wagers on the top three in varied amounts. I made exacta bets with varying base amounts by boxing the top two, boxing the top three and wheeling the top three against the next nine highest ranked horses and finally a $1 exacta with Frammento/All, "just in case".

Nice work

[flatstats]

The Titanic Will Never Sink
Backfitting is a bigger thief of time than procrastination x 10. It is one of the worst things a handicapper can do because not only does it give false results, it gives a dangerous false sense of security and it also wastes many hours, weeks and months of a handicappers time.

The reason for this is because a handicapper will never give up on his pet project. He will look at the results, refine it (backfit it), whittle away at it putting in so many hours such that he conditions himself to believe it can never fail.

The reality is though that it will fail because the handicapper is so oblivious to the truth that his method is so faulty to start with.

I am Robin Hood
Backfitting is akin to shooting an arrow at a tree and painting a target around it. You can shoot dozens of arrows at a nice row of Elms and when one hits the centre of such a tree you run up to it, get out your red, blue, and gold paint and paint concentric circles around the arrow. Marvel in the delight in showing off to your friends that you hit BULLS EYE. Yeee ha.

Now try the same shot again when everyone is looking at you; when you have your max stake on it. It's not going to happen.

Cluedo Handicapping
One of the most widely used type of backfitting is what I call Cluedo Handicapping. This is where a handicapper thinks something will happen again because he is convinced it is Mrs White in the Conservatory with the Lead Pipe.

The racing angle with this is on the lines of "4 out of the past 17 winners of the Epsom Derby had previously run at Royal Ascot as a 2yo", or something like "8 out of 11 winners of the St Leger had run over 12f last time out", or "25 grey horses have run in the York Ebor but none have won"

The problem with those stats is that they do not:

a) take into consideration the number of winners and starters in that group
b) take into consideration the prices of those runners

The other classic mistakes you can probably spot are the selective use of figures. Why use the past 17 winners for the Epsom Derby but only 11 for the St Leger? What was the timescale of those 25 grey horse in the Ebor? Were they all 2008 to 2015 or 1908 to 2015?

How To Avoid Backfitting
There is a simple statistical techinque you can use to prevent backfitting and that is to use sample sizes, chi square and sandboxing.

This involves looking at the results you have observed and firstly determining if the sample size is sufficient, secondly determining if the results are likely to be due to randomness. Thirdly you then wait from the date you observe results to when the 'live' sample size is sufficient.

But if you want to keep it simple just try this:

"If you can not justify why a rule or filter should be used then don't use it."

If you find that colts have a poor record in August and you can not work out why that is then don't rely on that fact. If you find that A Jockey is worse at B course but not C and you don't know why that is then don't use it.

Summary
Backfitting is pure evil. It is the biggest cause of failure for handicappers without question.

Handicappers would rather tap their bank out a dozen times because "just in case" their system comes good. They would rather be seen to be a mug that is losing, rather than a mug who didn't back a 25/1 shot because they gave up.

[thaskalos]

The fact that Helles's system picked this Derby's exacta cold is an encouraging development...but one's excitement is largely diminished by the disturbing fact that the system also selected Frammento as a better winning possibility than Dortmund.

All in all, more work on this method needs to be done, in my opinion.

[whodoyoulike]

Originally Posted by Helles

Buoyed by the success of the analyst picking the Oaks, I did use the output to make some Derby wagers.

Here is that output again:
18 American Pharoah 39|
10 Firing Line 25|
21 Frammento 11|
8 Dortmund 8|

Result 18,10,8,15

I made win wagers on the top three in varied amounts. I made exacta bets with varying base amounts by boxing the top two, boxing the top three and wheeling the top three against the next nine highest ranked horses and finally a $1 exacta with Frammento/All, "just in case".

Congrats, nice call and thanks for providing an update.

[Helles]

Thank you for your kind words TD.

[Helles]

Thank you, Saratoga Mike. I enjoy your posts.

[Helles]

A well-reasoned and well-written argument. If you read my posts, it should be clear to you I understand the problems with this approach as well as the miniscule size of the available data.

I thought the personal jab in your summary was wholly unnecessary. It made you come across as petty and angry.

[Helles]

Gus,

That is exactly what spurred me to start this thread. In 2009 how could Mine That Bird be ranked higher than Pioneer of the Nile or Chocolate Candy? In 2005 how was Giacomo rated higher than Afleet Alex?

Well, we know it's because Mine that Bird and Giacomo won those races and the algorithm was backfit to find those winners. What I still don't understand is how the same algorithm that found 50/1 horses also found 5/2 horses. Well, the 5/2 horses won too it could be argued. The algorithm was backfit to find them too. But how much do the 50/1 horses and the 5/2 horses have in common over the 48 factors used? It would appear they have plenty in common, but that is counter intuitive. This makes me ask the question, did Frammento have more in common with the winner that made Frammento an overlay? Albeit a losing one?

Does it mean at this highest level of racing there isn't much difference between the two extremes? They are all champions after a fashion and have plenty of heart?

I don't know the answers and I don't defend the methodology. I am simply puzzled by the results.

Of course it could all be a coincidence too.