[Dunbar]

Just to add a couple of things to philscki's very good response...

The Beyer's are your starting point. You know from reading the book that they don't take trip problems or bias into account. If you think a horse lost 3 lengths by being checked in its last race, then you can adjust the BSF for that race up by about 5 points if it was a route race, less if it was a sprint. If you think there was a good rail bias all day and the horse you are capping ran along the rail, you should adjust the BSF down. How much? That's the tough part.

I actually work in "beaten lengths". I take an average of the BSF's for each horse's last 2-3 races, weighing the most recent race more heavily, then convert the difference between those averages to "beaten lengths". (If the hightest horse has an 80 ave and another a 77 ave, I'd use 5 beaten lengths for the 2nd horse if it's a route race.). Once I am working in lengths, I can adjust the lengths according to trip factors from the previous races, again weighting the most recent race more heavily. I can also give lengths of credit for how the horse's running style fits today's race. If it is the lone speed, I will credit it with some lengths. If it is running from post 12, I will debit some lengths, depending on the horse's style and the particular oval. You get the idea. The BSF's give me a good starting point for making these adjustments.

--Dunbar