It has been pointed out to me that what I described is not, strictly speaking, the profit factor.Quote from kut2k2:
Here's what I hope is the final upgrade to the System Achievement Score :
SAS == 4*k*max[ 0, E ]*PF*min[ 1, N/1000 ] ,
where
k is the solution to the Kelly equation (see the OP),
E is the expectation (%/100),
PF is the profit factor (see below),
N is the number of trades in the performance evaluation.
PF is the ratio of the gain total to the absolute value of the loss total.
PF == sum[ max[ 0, Ri ] ]_i=1toN / sum[ max[ 0, -Ri ] ]_i=1toN

I have actually a simply solution: The higher the Kelly, the better the system. I believe this is true.The purpose of the formula is to rank the systems that work. Thanks all the same.
Take 10 strategies, do a manual ranking of them based on your gutfeel / preferences / etc, then look for formulas that will rank them accordingly.
Include CL always-in / 1 contract in the mix if you want.
Good, with HFFT I'm seeing pf 1.9 and have [-5,+9].Yes, PF = 2 for system [ -1, +2 ].