Thorograph #'s- Past Derby Winners

[smuthg]

I went back through the numbers for past Derby winners over the 25 years and I was surprised to see how high some of the numbers were. Has there been a change in the Thorograph formula/numbers over the last several years? For example, according to T/G Ferdinand got a 7, Sunday Silence got a 6.1 and Real Quiet got a 3.3. With that as a backdrop, Barbaro got a -2. I was as big a fan of Barbaro as anyone, but was he that much better than those 3 or is it an issue of a change in the formula?