BA: Base Ability

In ZED, Base Ability refers to a horse’s innate mean speed, before the addition/subtraction of distance preference on either side. Simply put, it’s your “base” mean speed before the distance preference addition/subtraction around 1600m (where DP pivots around). Base Ability is independent from the horse’s distance preference and variance assignments at birth. Update: if you’ve used The Zedge, you know the importance of sample size in trusting the scores. As part of our upcoming metric update, we’ve done a massive overhaul of the main base ability metric, adding conditional logic to find the most reliable base ability metric based on where we have sample.

DP: Distance Preference

Distance preference is, simply put, a speed add-on/subtraction that results in your horse having an ideal distance away from 1600m. If BA was a stake in the ground at 1600m, distance preference is a plank laying across all distances whose degree of “tilt” represents strength of distance preference. As such, it adds ability to the strong side, and removes ability from your weak side. A DP plank laying flat across your BA stake would represent no DP and likely a horse whose best distance is 1600m.Using the same normalized times from our average race ELO, removing the effects of variance completely, we can create a BA+DP metric at every distance. Once that’s done, we can run a weighted average on either side of 1600 to derive a delta from the strong side to the weak side. That range represents a horse’s distance preference. It’s adjusted to a -100 to 100 scale where -100 equals the strongest short distance preference, 100 equals the strongest long distance preference and 0 represents no distance preference.

VAR: Variance

Variance is probably the easiest racing trait to visualize. Less easy to calculate. It’s a measure of a horses range of possible outcomes. A horse with extreme variance will typically have more placements at 1st and 12th (caveat for horses dominating the field in BA or DP), while a lower variance horse will find its placements bunched much closer together. To calculate a horse’s variance, we return in part to the average race ELO to use the highly correlated/average 6th and 7th place times in the race. We then compare that average (6.5th place time) to the ACTUAL race time, and adjust all horses’ times in the race by that amount to adjust for the ZED factor (a manipulation of the race times).While the most likely way Zed adjust race times is using Z-scores and Standard Deviations (as in, lower/raise every horse’s time by .5 of their SD), using that method is super difficult and requires having enough data on every horses in the race at that distance to adjust accurately. That almost never happens so it often ends up less accurate than a clean raw time addition/subtraction. At least for our purposes.

Race Count: Confidence Level

The downside of using only 1600m results is that we often lack sufficient sample. The race counts should be used as confidence levels in the 16BA scores (we’ve added conditional highlighting to help with this). For horses with above average variance, less than 25 races and the data can be very noisy, where a cold or hot streak can lead to a misleading finish pattern. 50+ and we’re feeling good about the data. As part of our update, we’ll apply 16BA as your BA metric when your horse has 50 races or more at 1600 OR has 25 races at 1600 and a VAR score average or below.