by Jeremy Plonk
April 26, 2021
Welcome to a continuing handicapping series for our Monday blog space, “Monday Myths.” Each week I’ll use the power of the Betmix database to take common handicapping assumptions and either support or dispel them with data. Betmix data powers the 1/ST BET app and its features like Angler and Birddog give data-minded horseplayers a treasure trove of information in which to query your own curiosities.
Casual bettors flocking to the Kentucky Derby Day card make it one of the best betting days of the year for finding enticing prices.
You’ll often hear seasoned horseplayers and racetrackers talk about the ‘dumb’ money in the Kentucky Derby pools, not only in the big race, but the supporting features. When betting parimutuelly, having once-a-year type of bettors in the pool gives the more-regular player a confidence boost. That casual money can also help offset the impact of the sharps who drive down prices on common days of the year.
I set the Betmix database for every Kentucky Derby Day card from 2013-’19 (dismissing 2020 when September pools were half-sized what we see in May). I wanted to compare those results and wagering habits against overall racing days at Churchill Downs, using all races locally from 2013-’19 as the comparison. I also looked at similar field sizes in some categories.
Derby Day favorites won 23.5 percent, finished in the money 51.8 percent and had a $1 ROI of $0.70.
Churchill Downs favorites won 34.14 percent, finished in the money 68.4 percent and had a $1 ROI of $0.83.
Derby Day favorites in field sizes of 10 or more won 20.4 percent, finished in the money 44.9 percent and had a $1 ROI of $0.65.
Churchill Downs favorites in field sizes of 10 or more won 30.0 percent, finished in the money 61.2 percent and had a $1 ROI of $0.82.
Derby Day favorites had an average finish position of 3.79.
Churchill Downs favorites had an average finish position of 2.94.
Derby Day favorites in field sizes of 10 or more had an average finish position of 4.20.
Churchill Downs favorites in field sizes of 10 or more had an average finish position of 3.49.
Derby Day favorites had average odds of 2.09-1.
Churchill Downs favorites had average odds of 1.61-1.
Derby Day average winners were 6.24-1 odds, paying $14.48 for a $2 bet.
Churchill Downs average winners were 5.05-1 odds, paying $12.10 for a $2 bet.
Derby Day boasted a 10-1 or higher winner every 5.59 races on average (17 of 95).
Churchill Downs boasted a 10-1 or higher winner every 9.10 races on average (631 of 5745).
Favorites were less reliable on Derby Day by 10 points whether or not you considered field size. Derby Day favorites consistently finished farther behind in the pack than typical Churchill Downs chalk, again, regardless of field size. The favorites on Derby Day go off higher in price than a regular day at CD, and the average winner on Derby day paid $2.38 more on average for every $2 win bet. And as for longshots, they were considerably more likely to pop on Derby Day than a regular race day by a sweeping margin.
There’s no doubt about this one. Whether you want to call it casual, new or even dumb money, Kentucky Derby Day has proven to be a more lucrative day to swing against the favorites and cash an overlay price … or even swing for the fences.
You can go into Betmix and run your own queries for a deeper dive into this theory and any that you can create. For instance, you can sort by trainers on Derby Day only and see which have delivered when expected. Todd Pletcher (3-for-5) and Al Stall Jr. (3-for-4) have handled Derby Day business when favored. Put the power of big data in your corner.