Small Sample Size?

[coljesep]

Really appreciate the dialogue here!

[Tom]

FYI, you'll notice that you start off with a 400 vCash amount. I understand that each time you divulge or provide helpful info, you're awarded an addional 25 vCash.

Yes, that is true.

[raybo]

Dang, I guess I've been wasting my time here!

[whodoyoulike]

Don't think I haven't noticed every time you post.

[raybo]

Originally Posted by clemkadiddle

I trust my own work. When I have the same horse running different distances...or even the same distance for that matter in the current form cycle and the speed ratings vary...my calculations ironically put these efforts within a point.

Not that I am really calculating pace, BECAUSE I DON'T. I use pace to calculate THE AMOUNT OF WORK BEING PERFORMED IN THE COURSE OF THE RACE.

That is the only true measurement...because distance becomes taken out of the equation and the confusion that varying distance poses to handicapping also disappears.

For instance, how would anyone liked to have had Danza in the Arkansas Derby? I didn't have him, I admit...but I used that race in my research and now I have a tool that puts him right in the midst. In fact, his prior race as a 2YO at 6.5 furlongs killed anything in that field. You can bet the next time an opportunity like this presents itself I will get my hooks into it.

I also used Chitu's 6 furlong effort prior to the Robert B. Lewis as part of my research, in order to validate my calculations on Danza.

At this point I would be tempted to divulge the foundation behind this algorithm. For the moment, think about the point where a horse starts to expend racing energy rather than gallop. That's the point where one needs to start their research.

Well...gotta go for now. I have several races to review for Saturday and the data entry task awaits.

Hmmm - I thought horses start expending energy/doing work as soon as the gate opens, and that sometimes they start expending energy before the gate opens.

We wouldn't want you to divulge your hard work, so do yourself a favor and keep it a secret.

[thaskalos]

Originally Posted by clemkadiddle

I trust my own work. When I have the same horse running different distances...or even the same distance for that matter in the current form cycle and the speed ratings vary...my calculations ironically put these efforts within a point.

Not that I am really calculating pace, BECAUSE I DON'T. I use pace to calculate THE AMOUNT OF WORK BEING PERFORMED IN THE COURSE OF THE RACE.

That is the only true measurement...because distance becomes taken out of the equation and the confusion that varying distance poses to handicapping also disappears.

For instance, how would anyone liked to have had Danza in the Arkansas Derby? I didn't have him, I admit...but I used that race in my research and now I have a tool that puts him right in the midst. In fact, his prior race as a 2YO at 6.5 furlongs killed anything in that field. You can bet the next time an opportunity like this presents itself I will get my hooks into it.

I also used Chitu's 6 furlong effort prior to the Robert B. Lewis as part of my research, in order to validate my calculations on Danza.

At this point I would be tempted to divulge the foundation behind this algorithm. For the moment, think about the point where a horse starts to expend racing energy rather than gallop. That's the point where one needs to start their research.

Well...gotta go for now. I have several races to review for Saturday and the data entry task awaits.

So...it is your contention that horses NEVER run "bad races"?

[whodoyoulike]

Originally Posted by Dave Schwartz

I am not saying that 1,000 races is "enough." He asked about Z-tables starting at sample of 30. I was simply saying that 30 winners in a category was required to get a z-score on that category.

Think of it like this: I have 30 bets at 30/1. If I have 2 winners out of 30 should I be excited? Probably not. However, if I had 30 winners out of 450 bets that is time for some degree of excitement.

30 starts in that category is pretty worthless.

I think you've changed the scope of the OP's question. I was responding to Actor's comment of at least 20 for an adequate sample size in post #3. But, continuing with your line of thinking, say you were looking at (30-1) odds winners for a:

6f race on the dirt for males 3up and the reason the (30-1) won was

A. Most of the field ran the 1/2 in 43 - 44 while the (30-1) ran it in 45.5 - 46.5

or

B. The (30-1) won because they were able to improve their form and run the 1/2 in 44.8 - 45.5

Which would you rather do, analyze approx. 30 representative races or 1000? How many of the 1000 races would you review before you were comfortable to make a decision? Would it be 750, 850 or 1000?

I realize Tom would have made up his mind after 3 but, I suspect it's because he's a degenerate horse player (seems like a lot of us are on here).

[Tom]

For instance, how would anyone liked to have had Danza in the Arkansas Derby?

I bet him.

[castaway01]

Originally Posted by therussmeister

Not so much short term, but being one of the first ones to use a methodology/angle. If I use an 1,000 race sample to verify profitability before betting, that makes me 1,000 races too late.

I'm with you and Tom on this. I like to play trainer angles, and you've got to move early and before everyone else is onto it. Once the angle becomes obvious then even if the trainer is still winning, there's usually not much money to be made. I respect the guys who are grinding out profits with huge databases to determine what works and doesn't, but I believe in striking while the angle is hot.

[raybo]

Originally Posted by castaway01

I'm with you and Tom on this. I like to play trainer angles, and you've got to move early and before everyone else is onto it. Once the angle becomes obvious then even if the trainer is still winning, there's usually not much money to be made. I respect the guys who are grinding out profits with huge databases to determine what works and doesn't, but I believe in striking while the angle is hot.

IMO, large database players and small database players are operating in totally different worlds. The large database players are probably more likely to stay with a certain method longer than the small database player, who is constantly updating his smaller database with recent races and deleting older, less valid races, from the database.

[TrifectaMike]

Originally Posted by coljesep

I am wondering as you tried to develop your own "system" so to speak, or things you look for inside each race... what do you consider a good enough sample size of races? 100? More?

Whatever sample size makes you happy plus 1

Mike

[TrifectaMike]

Originally Posted by DeltaLover

I disagree.

The reason lies in the evaluation of a specific TV estimation algorithm..

Think about...

How you are going to decide that one algorithm is better than the other? Do you have any ideas?

Great question DL... followed by the beauty of silence

Mike

[clemkadiddle]

Here's a sampling. The first line "pace figures" are simply the FPS adjusted for variant and turned into a usable number. To get the FPS, add 80 and divide by 3. The "work" figures are where the analysis is made on how much energy spent in the race. The running total is a collection of the "work" during the race; the grand total is the final figure. There's an additional algorithm that's made on this series. All I can say is that I only bet dirt races at 8 furlongs and over; the horse with the better late numbers gets the distance.

Gulfstream 2nd, 7-12-14

01. Chilean Boy
furlongs 2.0 2.0 2.0 2.0
pace figures 80 82 83 74
work/furlong 6.3 6.8 7.2 4.7
work subtotal 12.6 13.7 14.4 9.5
work running total 26.3 40.7 50.2

furlongs 2.0 2.0 2.0 2.3
pace figures 84 82 78 74
work/furlong 7.4 6.8 5.7 4.8
work subtotal 14.8 13.6 11.4 9.6
work running total 28.4 39.8 49.4
================================================
02. Wrol Up
furlongs 2.0 2.0 2.0 1.0
pace figures 94 90 77 65
work/furlong 10.9 9.6 5.5 2.5
work subtotal 21.7 19.1 11.0 2.5
work running total 40.9 51.8 54.3

furlongs 2.0 2.0 2.0 2.3
pace figures 83 82 77 71
work/furlong 7.2 7.0 5.6 3.8
work subtotal 14.4 14.0 11.2 7.7
work running total 28.4 39.5 47.2
================================================
03. Whiskey Tap
furlongs 2.0 2.0 2.0 2.0
pace figures 82 92 83 72
work/furlong 7.0 10.0 7.2 4.1
work subtotal 14.0 20.0 14.5 8.1
work running total 33.9 48.4 56.6

furlongs 2.0 2.0 2.0 2.5
pace figures 81 88 83 69
work/furlong 6.5 8.8 7.3 3.5
work subtotal 13.0 17.6 14.6 7.0
work running total 30.6 45.2 52.2
================================================
04. Red Hills
furlongs 2.0 2.0 2.0 2.5
pace figures 82 86 83 70
work/furlong 6.9 8.0 7.1 3.7
work subtotal 13.9 16.0 14.3 7.4
work running total 29.8 44.1 51.5

furlongs 2.0 2.0 2.0 2.0
pace figures 81 91 84 71
work/furlong 6.7 9.8 7.4 4.0
work subtotal 13.4 19.6 14.8 7.9
work running total 33.0 47.8 55.7

 
================================================
05. Feels Like Flying
furlongs 2.0 2.0 2.0 0.5
pace figures 94 91 75 63
work/furlong 10.7 9.8 4.8 2.1
work subtotal 21.4 19.6 9.6 1.0
work running total 41.0 50.6 51.7

furlongs 2.0 2.0 2.0 1.0
pace figures 95 91 78 64
work/furlong 11.2 9.8 5.7 2.4
work subtotal 22.4 19.7 11.4 2.4
work running total 42.1 53.5 55.9
================================================
06. Giacomo the Great
furlongs 2.0 2.0 2.0 1.0
pace figures 95 87 75 66
work/furlong 11.1 8.3 5.1 2.9
work subtotal 22.3 16.6 10.1 2.9
work running total 38.9 49.0 51.9

furlongs 2.0 2.0 2.0 2.0
pace figures 90 84 73 68
work/furlong 9.3 7.4 4.3 3.1
work subtotal 18.7 14.8 8.7 6.2
work running total 33.5 42.2 48.5
================================================
07. Global Question
furlongs 2.0 2.0 2.0 2.0
pace figures 85 87 79 71
work/furlong 7.8 8.5 6.0 4.0
work subtotal 15.7 17.0 12.1 8.0
work running total 32.7 44.8 52.8

furlongs 2.0 2.0 2.0 2.0
pace figures 80 86 80 75
work/furlong 6.4 8.0 6.2 4.8
work subtotal 12.7 15.9 12.4 9.7
work running total 28.7 41.0 50.7
================================================
08. Double Judge
furlongs 2.0 2.0 2.0 0.5
pace figures 99 95 75 60
work/furlong 12.6 11.1 4.8 1.6
work subtotal 25.3 22.3 9.7 0.8
work running total 47.6 57.2 58.0

furlongs 2.0 2.0 2.0 1.0
pace figures 98 92 80 64
work/furlong 12.3 10.2 6.4 2.3
work subtotal 24.6 20.5 12.7 2.3
work running total 45.1 57.8 60.1
================================================

[Fingal]

Originally Posted by raybo

IMO, large database players and small database players are operating in totally different worlds. The large database players are probably more likely to stay with a certain method longer than the small database player, who is constantly updating his smaller database with recent races and deleting older, less valid races, from the database.

Personally I look at sample size as it relates to confidence. When I started back in the 80's I would have a years worth of DRF's, then it progressed to only a meet or a month, currently on the desk next to me it's only a week. Now it's more of a confirmation of my methods.

[traynor]

Originally Posted by Fingal

Personally I look at sample size as it relates to confidence. When I started back in the 80's I would have a years worth of DRF's, then it progressed to only a meet or a month, currently on the desk next to me it's only a week. Now it's more of a confirmation of my methods.

I think it is really quite simple. If one is seeking Truth-With-a-Big-T, one needs a VERY large database, and will probably spend one's life (as MANY others have and continue to do) chasing rainbows. And very little time wagering (or, if wagering, making little or no profit).

If one is seeking profit, one uses whatever size "database" one has found to be profitable, using whatever methods one has found to be profitable. Take the money, keep the profit, enjoy life. It is that simple.

Personally, I eschew both databases that are too large and databases that are too small. Like Goldilocks' porridge, my databases are just right. However, that is only true for the specific methodology I use. YMMV.