Don't Look Amateurish By Falling Into The 4YO vs 3YO Trap

[sham]

BB, you are correct sir and here are the stats from my data base of 110 or so champion racehorses going back to 1900.

Avg imp 3yo vs 2yo - 14 lengths (projected to 10fl)
Avg imp 4&up vs 3yo - 4 lengths (projected to 10fl)

About 70% of horses that went on to race as older horses improved their average running times. About half of the 30% that did not improve had injury related issues. In summary, there is a 70%-85% chance that a horse will improve as a 4yo by an average of 4 lengths as compared to his 3yo season. Here is the data on the specific horses you mentioned (4yo vs 3yo seasons):

Slew - improved 4 lengths (projected to 10fl)
Bid - improved 6.8 lengths (projected to 10fl)
Fager - improved 5.6 lengths (projected to 10fl)