In racing literature and messaging, bias is a common topic.

Bias is usually focused on a few winning efforts over a few days or even a few races.

But in studies of topics other than bias, we usually talk in terms of a very minimum of 30 wins before we consider there to be any trend. So, why do we look at such a small sample of bias when that is contrary to our normal habits?

Now, certainly, inside horses run a shorter distance than outside horses, so there is going to always be an advantage to the inside. Just look at the starting positions of human sprinters... starts are staggered to avoid lane advantage. Does the positional bias in horse racing shift?

And, studies clearly do show that front runners win more often than closers.

In winter, there is an explanation for the combination of inside and early speed bias. The horse that gets the early lead can take a firm inside ground for a shorter distance and pelt the trailing horses with ice and other solid particles that sting (the jockeys and probably the horses, too) in the cold weather. So, there is that.

Do you trust an inside/outside bias or an early/late speed bias off of a small sample? Or is it really mostly based on the random chance of which horses are in assigned positions (gates) in the races? What do you think? How much of your handicapping relies on bias?