I think RB means an explanation of how the FICO model works, which we will never see.
I have heard it is some sort of Black Scholes model as shown below for the first time:
C(S,T) = S\Phi(d_1) - Ke^{-rT}\Phi(d_2) \,
where
d_1 = \frac{\ln(S/K) + (r + \sigma^2/2)T}{\sigma\sqrt{T}}
d_2 = \frac{\ln(S/K) + (r - \sigma^2/2)T}{\sigma\sqrt{T}} = d_1 - \sigma\sqrt{T}.
Easy enough right?
Actaully I think the model will score it a little differently for each person because everyones file is different.
Credit score (United States) - Wikipedia, the free encyclopedia