The answer is the same as for determining track speed in general-- you look at how fast the horses run, relative to their figure histories. That's what the (misnamed) "projection" method is all about, and every single serious figure maker does it, from us to Beyer to TimeForm in the UK, and if you read "History Lesson 1 and 2" in the Archives you'll see it's been going on a lot longer than that. The difference is that Ragozin had made the assumption, with no basis in either science or logic, that tracks don't change speed during the card unless there is precipitation, a freeze, or a thaw.

That's a pretty ridiculous CONCLUSION to come to (let alone for Len R to say in his book he knows it for a fact), given that water is being added and evaporating during the day, and other work is sometimes done to the track. But the result of that illogic is, they use just one variant for the day (except when the specific conditions above exist). Which means when the track DOES change speeds, which happens about as often as it doesn't, they end up using what amounts to an average variant for the day, getting some races too fast and some too slow.

This is also true of their assumption that the relationship between one and two turn races is a constant. (On that note, Connie Merjos, first trackman for both TG and before that Ragozin, made his own figures for years before he met Len, and totally disagreed with him).

And if you want to see a perfect illustration of all this in practice, and you make figures, take a look at last Friday and Sunday at Monmouth. Track speed at that place has always moved around a crazy amount, presumably due to proximity to the ocean, and the tides. But not only are the routes there not tying to the sprints, the route variants themselves are extremely "slow" early, then getting much (like 8 points) faster late, with no weather. There was a lot of wind which may have dried the track, but whatever it is, if you blindly assume the track CAN'T change speed and use one variant for those days, you are completely screwed, as are your customers.