Thanks for your answer.

I understand that tracks don't stay the same speed. My question was more about the relative weight you give the time of a race (admittedly small relative to other figure makers, although I think you pushed back on Paul Matties's assertion that you seemed to ignore it entirely) versus past figures of the horses and whether those relative weights are changed if horses are going on or off Lasix. You've answered my question.

I'm surprised you don't think Lasix makes non-bleeders run faster. I thought the 5-pound penalty for running on Lasix you proposed some time ago was based on that assumption and the data you had at hand. Rather than a study, implementing your suggestion would likely provide more informative results. Would trainers giving up Lasix start winning more races?