Thanks for the replies guys, what I am trying to achieve is to find a value that represents the true merit in a run based primarily on the pace leading to the 600m. As mentioned if a race is run fast it will generally have a fast overall rating and vice versa if the early pace is slow.

The key is determining what performances are better than others, if a 100 rating equals the benchmark and horse "A" runs the early section in a 107 and the final 600m in a 98 to give an overall rating of 105. Horse "B" comes from a different race where the early pace was 94 and the final 600m he rated 110 to give an overall of 104. Which run was truly better?

Josh has come up with a multiplier formula to exponentially reward or punish the horses based on their early rating and it is something I am going to trial on some data and see how it looks.

I am open to other ideas on this so if someone else wants to have a look at it I can provide some sample data.

Cheers,

Mat.