There are dozens of systems for picking horses, some good and most bad. There’s the gray horse method, the wife’s birthday method, the “choose the horse that most recently defecated” method; I won’t list them all here. A few systems, however, are both popular and widely accepted as getting at something true, even if by itself they present an incomplete picture. I’ll discuss a few of those here.
A few words about the form: past performances are horse racing’s box form. They are an incredibly efficient way to transmit a great deal of information about what horses have done before. Reading the form isn’t difficult, but it can be intimidating the first time you see all the tiny-font numbers with even tinier-font numbers superscripted above them. To make use of these systems, you’ll have to be able to read the form. A helpful tutorial is provided here.
Speed Handicapping: Not as Easy as It Sounds: On its surface, horse racing seems like it should be an easy sport: the fastest horses win the most. And that’s true; the fastest horse wins every race (duh). But for decades and decades, handicappers learned to ignore final times. “Time only matters in prison,” so the adage goes.
Why would handicappers ignore the piece of data that tells you how fast a horse actually ran? Because horses all run on different tracks. Courses in the Southwest are hard and fast, like running on a sidewalk. Courses in the Midwest are deep, which slows down times. Even an individual track can run fast or slow on different days, or slow down or speed up within a single day of races. Sometimes races around one turn are fast but around two turns are slow. There’s too much wobble in the numbers to look at the final time and get anything useful from that alone.
But we can also control for the wobble. How this works is complicated, but a speed figure tries to control for the variations in time and different courses. The speed figure is a number based on the final time, but which only treats the final time as a starting point.
These figures (the most famous of which are the Beyer Figures published in the Daily Racing Form) are incredibly valuable, but understand their limitations. These figures are tied to nothing but final times, so they do not capture if a horse had a difficult trip around the track, or whether the horse slowed down before the wire because it was so far out in front or behind, or whether the horse had a minor injury, or anything else. They are nothing but augmentations of final time.
Pace Makes the Race (Usually): Horses have different styles of running. Some set the pace, while others are “closers” that make their moves just before the finishing wire. Horses can be trained to change their styles to some degree, but many have natural preferences that cannot be switched.
That being said, races on dirt (as the Kentucky Derby is) are run in one style: fast. Early speed horses run as fast as they can early and hope they have a big enough lead to hold on. Closing horses run as fast early as they do late (but usually not faster: their hard gains late are usually an optical illusion, and their pace has stayed the same throughout the race. But there are exceptions; Secretariat ran every quarter mile of his Kentucky Derby faster than he ran the one preceding it, which is ridiculous).
In a slow paced race—that is, a race in which the horses go slower than usual early—the horses near the front find themselves with more energy late, and the horses in back can’t go fast enough to catch up. In a fast-paced race, the horses in front burn themselves out and the ones in back catch up at the end. A thoroughbred that can stay up front through a hot pace and win is very good, better than a closer that wins in the same conditions. Horses that have won from behind in a slow race or won from the front in fast races deserve extra credit for their speed figures (some handicappers produce “pace figures” that mimic speed figures; these are rarer but useful).
Fortunately for handicappers, the Derby tends to get run at only one of three paces: average, fast, or suicidal. There are almost no slow Derbies; there are too many horses, and a few will get out and set the pace quickly if nothing else but to avoid having to fight traffic later. That doesn’t mean that you can dismiss a horse that is likely to be up front. But you can dismiss a horse, especially from win bets, who absolutely needs the front—the type of horse that hates getting dirt kicked in its face or being surrounded by other runners and will go as quickly as necessary to set the pace. These horses are fried before the homestretch.
So the Derby is a closer’s race, but be warned: much has to go right for a deep closer to win. With 20 horses, many of which are fading quickly in the final stretch, traffic can become a nightmare for horses in the back. Just last year, Ice Box ran perhaps the best race in the Derby but had to fight around too many other runners to get up in time. In the perfect world, you’d like to be positioned somewhere near the front, but far enough back to maintain a reasonable early speed.
Class Handicapping: Not Terribly Helpful in this Context: Before speed figures, class handicapping was the king of methods. Is the horse facing better or worse this time out? Is he stepping up or dropping down? Is a $15,000 race for non-winners of three better than a $20,000 race for non-winners of two?
Class handicapping still has its place for everyday betting, but all the horses in the Derby have been running in classy races. Besides, everyone is stepping up in class for the Kentucky Derby. That no one knows who will handle the “class” best is part of the fun, and the challenge.
Trip Handicapping: The Hidden Weapon: Horse racing isn’t run on a sprinter’s track. The competitors in the Derby won’t have paths marked on the ground, and there will be all sorts of bumping and jostling. At least six horses on Saturday will have no chance because of how the initial “cavalry charge” shakes out. There is very little a handicapper can do to mitigate this.
But, they can also use trip knowledge to their advantage. For example, was a horse far off the rail on the turns in their previous races? If they were, they ran a further distance than the other horses in that race. Or, was the horse bumped leaving the gate? If so, perhaps they have an excuse for a bad effort. There is also a theory that tracks can develop biases, either towards types of runners (early speed horses have an advantage) or towards spots on the track (the theory behind Mind That Bird's upset win is that the area near the rail was harder than the rest of the track, so Calvin Borel took his mount on the freeway while rest of the field was traveling on a country gravel road). I think biases do happen, but the most common bias is confirmation bias ("longshot won from the front of the field? Speed bias!")
Unlike the above methods, you can’t really trip handicap only by looking at the form. True, the past performances will give you a line about what happened in the race, but that line can only capture a small fraction of the trip knowledge. The good thing about the Derby in this modern era of ours, however, is that all the prep races can be found on YouTube. Punch up the race, watch the horse, and see if he had any trouble.
One word of caution, though: as discussed above, closers tend to have more trip trouble because they have to pass tired horses in the homestretch. If a horse is a committed closer, this is a problem he will face in every race, though not always to the same extent. Don’t automatically bump a closer up just because he was forced to go wide or because he had to change courses, unless you think that this won’t be true in the next race.
Breeding and Dosage: the Astronomy and Astrology of Horse Racing: The modern thoroughbred has been meticulously inbred. Everythoroughbred racing today, from the Kentucky Derby favorite to the cheapest maiden claimer in the US, is the descendant of three stallions from the 17th and 18th century. In some ways, even this overstates the diversity, since 95% of the horses can trace their Y chromosome back to one early 18th century stallion, the Darley Arabian. And several other bottlenecks have occurred more recently, with Native Dancer (through Mr. Prospector, among others) and Seattle Slew (through A.P. Indy, among others) have been particularly important.
Breeding is as much art as science, and is as much luck as either; genetics is nothing but probabilities, and the chances of creating a great horse, regardless of the stock you use, are very slim. But it is a science, and there are definite statistical tendencies. Some lines prefer the turf over dirt, while others love muddy tracks. Some have trouble with stamina, while others fail to show early speed. These are nothing more than tendencies which can be extrapolated from data sets, but when a horse is trying something new (as is true of all Derby participants), sometimes pedigree is the best we have to work with.
Breeding is science. Dosage theory is a peculiar pseudo-science derived from breeding and genetics. According to Dosage theory (I'm oversimplifying here), stallions--referred to ostentatiously as "chefs de race"--fit into one of five categories, ranging from "brilliant" (fast but tires quickly) to "professional" (slow but great endurance). If you assign a number to each stallion in a horse's bloodline for four generations based on that stallion's aptitude and plug those numbers into an equation, the equation will spit out a number. That number represents the talent of the Derby participant: too high, and the runner won't get the distance, but too low and the runner won't be fast enough. (I took out a lot of details in that description. If you're interested, read this).
As a heuristic, Dosage might not be a bad way of finding horses whose pedigree might not hold up. But many Dosage proponents claim much more than that. But lots of Dosage people claim much more than that, thinking that Dosage is the One True Method of winning the Derby. And generally, horses within the acceptable dosage range have won the Derby.
But there are many reasons to be skeptical. First, Dosage applies only to the Kentucky Derby and maybe the Belmont; it apparently doesn't work for the Preakness, which is only two weeks after the Derby and almost the same distance, or any other race. Second, the Dosage people assign the stallions to categories, and they've been known to fiddle with the categorizations until they "work." Finally, Dosage hasn't even been all that successful lately; five of the past 20 winners have been outside the range, with Mine That Bird being the most recent. Considering that most participants fall within the acceptable Dosage range, this isn't a fantastic record.
Some people still swear by the method though, and you might hear some of the terms bandied this week. I tend to think these people are either kooks, or the types of folks that put definite articles behind nouns like Google. To each his own, but Dosage is not part of my toolkit.