Actually I think it does make sense and isn't nearly as broad a field as you took it to be. I'm not competent to answer the question, but if memory serves W is something called the "maximum likelihood" function, and we take the logarithm of that for some reason which my memory fails me on. I think that is what the op assumed we knew. (I ran into this in a graduate lab ages ago when we were talking about the derivation of

formulas. I never really understood the derivations, but I could use my notes to derive the correct formulas anyway.)

-Dan