When betting with stats, make sure they're up to date

August 1st, 2023

Bettors who employ statistics in their handicapping—trainer stats, jockey stats, sire stat, etc.—should ask themselves from time to time whether their favorite angles are still relevant, or if the data is telling a new story.

After all, stats aren’t frozen in time. They change with every race, and over time, those changes can add up. An angle that worked great for a few years may quietly shift to where it’s no longer lucrative, and staying on top of these developments is critical to ensure you bet the right horses.

Consider, for example, trainer stats involving first-time starters. Some trainers are known to excel with debuting runners, and others have reputations for letting their horses develop slowly. Once you’ve learned that “Trainer A” wins with a high percentage of first-time starters, it’s possible to fall into a trap of viewing every first-time starter conditioned by Trainer A in a positive light, even if—as the years go by—Trainer A’s win percentage with such starters gradually drops.

The opposite can also happen. Maybe “Trainer B” is an infrequent winner with first-time starters, so you never bet Trainer B’s debuting runners. Until one day it crosses your mind that you’ve been beaten by Trainer B’s first-time starters more times than you can count, and you check the stats and realize Trainer B is now a 20% winner with first-time starters.

Real-life examples include John Shirreffs and Michael McCarthy. In the past, Shirreffs had a reputation for saddling ready-to-win first-time starters; as recently as the mid-2000s he was winning with as many as 20% of his debuting runners per year. Nowadays, it’s uncommon for Shirreffs' trainees to win on debut; they regularly improve second time out, and that’s when bettors are attuned to bet them. Recent examples include Honor A. P. and Express Train, Grade 1 winners who finished second on debut before winning second time out at short prices.

On the other end of the spectrum is McCarthy. In 2019 and 2020, his win percentage with first-time starters was 4%; in 2021, it was a modest 8%. His win percentage with second-time starters (21% at the time) was much more encouraging, so bettors knew to generally avoid McCarthy trainees first time out and consider betting them when they ran for the second time.

But now the storyline is shifting. McCarthy’s win rate with debuting runners improved to 13% in 2022 and stands at 21% as of July 31, 2023. That was the day that McCarthy’s first-time starter Blue Eyed George overcame trouble to rally and win a one-mile maiden special weight over the Ellis Park turf course at odds of 9-2.

Just one day earlier, McCarthy’s unraced colt Endlessly had debuted in a one-mile maiden special weight over the Del Mar lawn. Sent off at odds of 29-10, Endlessly battled between rivals to kick clear in the final furlong and win by 2 1/4 lengths.

Keeping an eye on the up-to-the-minute nuances of trainer statistics can yield enticing payoffs when longstanding angles start to shift. It’s well worth the effort.