I appreciate these comments and the obvious time taken to make them, but feel compelled to clarify my position. I am well aware of factors such as as track variance, sectionals, early speed and endorse their proper use.

However I was trying to keep the discussion as simple as possible, partly for the benefit of Dr Ron and billivet who are just starting out on this exercise.

Now, I have only one issue with osulldj and La Mer and perhaps the rest of humankind, namely:

Typically it's wrong to make time comparisons from different meetings. And that's what averaging is, in a roundabout way. So averaging times is wrong.

Official track readings are notoriously untrustworthy so there could be even 1 second's difference between two allegedly good tracks. Penetrometers also appear fishy, perhaps because those readings are performed many hours before the races start.

Therefore I only make comparisons between races at the same meeting.

So in the earlier Kembla example, there were 43 Opens and 167 Maidens available, but I was only prepared to compare the 29 matches on identical days.

By contrast I assume osulldj would average the most middle of the road 35 Opens and 133 Maidens.



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La Mer's independent data is very useful. I note he calculates the difference between 1200m Maidens and Opens as 1.22 seconds. Precisely the same difference I found using my different techniques.

However the Class versus Open differences are 0.81 versus 0.76. Or ~half a length. Not too bad considering timing to 100th's a second only started there in 1997.

It's also fascinating that he finds that the superior Class 2's have inferior times to Class 1's. Confirming my earlier claim.

But to my amazement I note that my technique finds Class 1 races are 0.88 inferior to Opens, hence 0.12 inferior to Class 2. Which is the way you'd want it to be. (Although untrimmed averages also get a 0.08 difference in the right direction).