They run an opening quarter in 24, and the half mile went in 47 and 3, the lead horse is an experienced grade two racehorse who is getting everything her way- it’s her race to lose. Even with the tepid fractions her usually cool, calm and collected journeyman jockey knows that he’s in for a dogfight. You see, there’s a freight train 15 lengths behind him and her name is Zenyatta. This isn’t another Zenyatta blog. This is a blog about why confirmation is so important when evaluating juveniles and what measurements to look for and which ones you should ignore.

Several years ago, the Jockey Club published a landmark study in which they studied 260 foals and recorded seven measurements for each one. The measurements were as follows: wither height, hip height, body length, distal limb length, cannon circumference, heart girth and chest width. These seven measures were then weighed against each horse’s win percentage to see if there was a relationship- or correlation between that particular measurement and a horse’s win percentage. The results were close to what you would think they would be.

So here’s some statistics 101. A correlation coefficient is a measurement on a scale of -1.0 to 1.0 of how much the value of one variable impacts the value of another variable. A correlation of 1 means that the two variables are in a perfect and positive linear relationship with one another. A negative value means that the first variable negatively impacts the value of the second variable. A positive correlation of .30 or greater is considered relatively strong but not an overpowering factor.

Looking at the chart, there is only one value that meets our .3 threshold; Hip Height for fillies, but there another one that comes relatively close and that is body length for fillies. Of course, statistics isn’t perfect and is open to interpretation. Now, considering that juveniles exclusively run sprints- with the exception of the Breeder’s Cup Juvenile races and the Nashua – basically three races out of over a thousand- it is remarkable that heart girth managed to score a .27 correlation coefficient. Imagine if half of the races contested were routes.  It is safe to assume that heart girth would’ve climbed to .35 and been the biggest correlation component for both genders. Now, why is hip height so important for females but not males, who knows? My theory is that there are fewer females with massive hip height than there are males so the females like Zenyatta who have this type of hip height really stand out.

So, looking at the chart, body type, in particular hip height is a great predictor of success in fillies but less so in males, but keep in mind that only one measurement even met the .30 threshold so I wouldn’t go and play an unraced juvenile purely based on measurements even if she looks like Zenyatta.