TGJB,

"....is one of the ways I know that Andy is using pars at some point in the process (another is the relationship between certain circuits, or more specifically certain types of circuits)."

This is what I know.

He is using projection figures for a "minimum" of all the major circuits and has a database of every figure for every horse.

When horses switch circuits the computer system examines the horses' figures and will flag any discrepancies that are consistent enough to know that one of the circuits is in error. An adjustment can then be made.

In other words if horses coming from track "X" are running "Y" slower when they leave for other tracks, he knows that track "X" is too fast.

I know that he keeps pars for all the tracks, but if he uses them in the process at all, it's only for the very tiny tracks. If those tracks get out of whack, they are brought back in line as horses from those tracks move circuits with projection figures (same as above).

IMHO, there is no way to be certain about anyone's figures over time despite the fact that many helpful techniques are used.

Every figure maker has biases in their interpretation of results (things like the impact/lack thereof of pace, position, weight, bias, moving up and down the class ladder, etc...) that slowly creep into the figures over time.

No one is more interested in making cross generation comparisons than I am, but I think we are all better off worrying about getting the current figures right than the relationship between decades.