Speed Figs

[dean smith]

Would someone explain to me how the Brisnet speed figures differ to the Beyer speed figs? They seem pretty comparable when dealing with horses and races of the highest class (a 117 Beyer is pretty close to a Brisnet 117 in the BC Classic, for instance), but the lower you go down the allowance and claiming ladders, the discrepancies seem to become much greater (the lowest bottom-feeders seem to have a hard time dropping below a low 50s Brisnet, for instance).

Does anyone know the differences in the way these figures are arrived at, and if I'm using the Brisnets, is there any adjusting that needs to be made to my own handicapping (having learned most of what I know through books and articles that deal with Beyer figs)?

Twin Spires users might have a better idea of what I'm talking about, although I'm not sure what PPs other sites use.