Originally Posted by

**the42up**
I prefer to use r for mixed effect models. The syntax is pretty simple and intuitive, i.e. in the following regression:

response ~ random effect + random effect + (1|fixed effect) + (1 + variable that affects slope|fixed effect)

The (1|fixed effect) term is for the intercept, and the other is for the slope. Pretty easy syntax.

But to answer your question, yes, you do need to incorporate a fixed effect (subject) into your model. Mainly what you seem to be talking about is something called psuedoreplication.

a generalized linear mixed model would be the correct solution. Just include a fixed effect term to take care of the psuedoreplication.

Good luck!