I didn't get into it here because Tony indicated he is not into pace. but I can cover it however much interests everyone.
My interest is in % Median, a Sartin principle. It is based on the percentage of early pace versus late, early energy if you will.
So, I look at three factors: positional early (Quirin speed points), speed early (Sartin early pace, more or less early feet per second or else a comparison to early fractional par) and %Median (early energy).
The concept is that when a field of horses have a combined low %Median ( I actually take the combined median of each horse's median of its % Medians of all its shown races, obviously a computerized task) , then some of those horses are going to find themselves on the lead despite low early energy and are likely to exert more early energy than they are accustomed to and thus more than they can handle. This makes the situation ripe for a pace meltdown and a chaos race. Generally, my experience suggests that this is not a good way to bet against odds-on horses that don't seem to be bet against, though i have no data to back this up. In other words, I don't find this method to be stand-alone bet against on odd-on horses. Many of those are simply good enough to overcome the adversity.
People were very skeptical when I introduced this concept, but the next day I predicted a big longshot win. My memory suggests that it paid something like $47 to win, not sure. Granted, that was just one race, but I was 1 for 1 and I did it under the pressure of possibly looking like an idiot.
:)
I am still studying this method. It doesn't work on turf because many of those horses have low % Medians -- their big run is late. The same is also likely for all-weather (Tapeta, etc), though I have little experience with all-weather. I am also studying the extent to which the energy requirement changes per distance or whether that is very relevant.
As most of you probably know, chaos races often have huge payouts, sometimes 20/1 and more. These races that fall into the range for my method are scarce. My GUESS is that you would be unlikely to find more than 1 per week per track, but there is nothing to say that it would be impossible to find a lot in one week or none in a week.
Another gotcha here is that the % Medians all need to be recalculated based on scratches. So, I am working on a new program that will provide for scratch changes much faster than my prior program, which wrote out HTML files for entire cards.
And, one last known caveat is that chaos seldom ensues in fields of less than 6 or 7 horses. So, 8 or more entrants are preferable. Sheesh, in today's racing, that alone narrows the opportunities.
I also know people who model %Median by track and distance and severely downgrade the chances of horses that fall outside the range of their model.