oh and by the way you originally posted 15.2%. which is it, 15.2% or 16.2%. and that is not 12.5% better. "%" means per 100 you are getting 0.8 winners per hundred better which means 0.8% better. not terribly "significant.".
Thank you. Winston.

Winston,

As you appear to be a newcomer perhaps you may care to check out some of my earlier material where I tried to discuss proportional staking and related topics.

As far as I can tell there are no errors in my posted figures. The strike rate of 16.2% refers to the new control sample of 110,487 runners mentioned in the preceding sentence.

I believe the concept of expected wins and places is reasonably well known. I notice that ignorance of Actual/Expected happens to be a favourite bugbear of Anomaly Nick.

If you accept places as 1st, 2nd or 3rd, then for a field of N:

Expected Win = 1/N

Expected place = 3/N

just so I got this correct. in a field of 10 then
expected win = 1/10 = 10%
expected place = 3/10 = 30%
so i have 10% chance to win and 30% chance to place?
Thank you. Winston.

Very true. I've found a lot of work can go in to improving POT by a few measely % so the difference could be more significant than I think.
Be assured I won't be throwing out the baby with the bathwater, I'll just put in a few more tweaks based on position finished along with the other tweaks and see if it improves things. Then more likely than not abandon them as I do with the majority of things I try.

KV

Mr jfc.
you have had ample time to correct my mistake. you havent so I must be right. now to the consequences.
you are suggesting that every horse in a race of N has a 1/N chance of winning and a 3/N chance of placing.
please may i pick any horse and you give me N/1 to win and N/3 to place? you will be broke very quickly.
what you are doing is very similar to work of Roger Biggs and impact values. while i respect much of Rogers work i do not believe impact values are as good as the actual vs expected figures that Anomaly Nick talks much of.
if you were to show Nick the figures you suggest he will laugh his head off.

please do not make mistake that just becos i am new to this forum that i am uneducated in these matters. i feel that the above statement from you is very condescending.
Thank you. Winston.

Winston,

I did use Actual versus Expected expressed as a percentage difference.

Having just looked up Impact Values I note that they do not take field size into account whereas I base my Expected on field size.

Having again reviewed my material I can find no errors.

I don't understand your logic that if I don't correct your mistake then you are right. Presumably you meant to use some other word like "offering" rather than "mistake".

Typically I correct material when I believe there is a serious mistake likely to steer others in the wrong direction. I have noticed a number of mistakes you have made but did not comment because I assumed that most would be able to spot those errors, and it was of little consequence if they did not.

Mr jfc,
you convenient leave out my first part of post which asks if I pick a horse will you give N/1 odds to win and N/3 odds to place? this is at hart of the discussion so please to answer this part.

your figures are not "Actual versus Expected" under any dealing of this theory that i have seen and certainly not according to Anomaly Nicks interpretation of this figure. your "expected" is certainly not a true expected figure but more of a participation percentage. and this is why your figures are more like Rogers Impact Value figures.

by your own admission you have little knowledge of Impact Values therefore I respectfully submit you should not be making rash statement like this. Impact Values most certainly DO take into account field size.
knowing very much both impact values and actual versus expected theory i can tell you very much that your figures are more like impact values.

perhaps therein lie the problem.

now please mr jfc you have before berated others for calling mistake without showing proof or offering correction. please apply same expectation to you as to others.
Thank you. Winston.

Winston,


http://www.flatstats.co.uk/articles/impact_values.html

This free article defines and describes Impact Values, as well as providing a history of that methodology which preceded the computer commodity age.

Note that there is no mention of field size in that article.



You certainly are adamant that Impact Values do take field size into account, and that you are very knowledgeable about them. Unless you can prove that here in the face of the above contradictory material, I doubt that many will concur with your self-assessment.

Also do not misquote me. I have not admitted that I have little knowledge of Impact Value. Just because I just looked them up, does not imply that I gave them inadequate consideration, or that I made a rash statement.

Mr jfc,
hello. yes it is good article. have you actually read it?
i quote now from the article
if the 69234 runners mentioned were not the sum of the field sizes of the 6678 races then can you please tell me what they are? random number perhaps? i quote more.
IV=% of winners / % of runners
surely "% of runners" mean you must have field sizes for all races you consider?
is that enough proof for you?
Thank you. Winston.

This is precisely where one can go wrong with race modelling, or the information supplied can be misleading.

There are two glaring omission in these figures.

There is no research done on the form or class of those last time out winners.
At least half those runners had little or no chance of winning because of the massive class jump.

The conclusions drawn would be wrong.

Try the same statistics with top 3 API or career prizemoney and you'd see a massive jump in percentages.

Statistically, the last time out winners do win a lot of races, but are overbet in the market.

There is also no data on horses coming back from a lengthy spell, they could be last start winners also, but a great percentage could not win first up.

If one concludes they have a poor strike rate, one is not looking properly at the data.

I can get 48% win strike rate from last start winners with the correct filters compared with the 16.50% illustrated.

The author of the article has fallen into the greatest retrofitting pitfall of all time....

"But you should not look at the impact value figure in isolation. You should examine both the impact value and the ROI% figure.

A strong positive value for both of them is what you need to find as this indicates a group of horses who are winning more races than they should, and are going of at prices higher than they should."

This is the path to an empty wallet - guaranteed. He wants to use the impact values only which improve strike rate AND create profit, which is putting the cart before the horse.

The impact values should not be used on their own to "select" horses, as each horse has a different combination of factors and no two are the same, therefore the impact values, should be used to assign a rating to the horse based on combinations of POSITIVE impact ratios.

The final rating compared to the rest of the field will determine the fair price for the horse.

The punter will seek out the value runners for the race, and obtain value or pass the race.

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