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[delayjf]

I'm not sure if the below addresses your inquiry or not. Its from 2003, but I always found that discussion interesting. The poster was MV McKee, who know longer post here.

Over the past few years I have attempted to use a couple of methods to try and extrapolate pace variants from my final time variant.

1) Use a fraction of the final time variant that represented the proportion of race distance that the fractional time represents.
Example: 6f 1/4, 1/2, 3/4 = .33, .33, .33

2) Use a fraction of the final time variant that represented the proportion of race time that the fractional time represents.
Example: 6f 22 46 72 = .306, .333, .361

I have never achieved my desired results when using ratings and variants derived from these formulas in practice.

In my opinion, this is because in using either of the methods mentioned above (in particular method 1) you are utilizing the final time variant as an expression of the speed of the track (and possibly the wind) only. I feel that a final time variant is a product of not only the effect of a racing surface on a horse's speed, but also upon his stamina.

I actually came to the conclusion that it was best practice to calculate the individual fractional variants on a day by day, track by track basis, but extrapolating these variants from the final time variant is generally quite accurate, and in cases where I cannot get a high confidence level for a given day using the former method, I will use the final variant(s) as the basis for their fractional counterparts.

However, I have found that the following proportions are far more accurate for doing this.
In the case of 6 Furlong races:
1/4 (1) .20
1/4 (2) .32
1/4 (3) .48
1/2 (1) .52
1/2 (2) .80

In other words, if I had a final variant that made the track 1 second fast, I would (on average) have the 1st 1/4 of a 6 furlong race adjusted .20 seconds fast. Of course this varies slightly from track to track and day to day, but from my research and practical use, this is a very solid average.

To me, the reason for this distribution became obvious (after about 3 years of having no clue). Like pace, a track variant (be it fast or slow) has a cumulative effect. When I am saying that the final 1/4 of a 6 furlong race is (.48 X Final variant) seconds fast/slow, I am not saying that the section of the track surface from the quarter pole to the wire is that fast/slow. Rather I am stating that the track speed/energy returned have a cumulative effect of X on the final 1/4. In the case of the First 1/4, there is no cumulative effect (unless you want to make a very fine-line distinction and argue that the first 1/8th affects the 2nd 1/8th, etc.)

Did any of this make sense?