[R-sig-ME] Compare goodness of fit between models

[Sverre Stausland]

Dear mixed-models helpers,

say I have a study where I try to predict people's response to how
happy they are on a 1-5 scale. The data frame has the dependent
variable "Response" (1-5) and a random effect for "Subject". I fit a
model with the fixed effects "Height" and "Income". I also fit a model
with the fixed effects "Weight" and "Hours of sleep". In this case
where the dependent variable, subjects, and the number of observations
are the same in the two models, am I justified to directly compare the
goodness-of-fit values for the two models?

Please note that this is a hypothetical example. I know that I in this
case should just fit a model with all four fixed effects. In the real
case I have, that is not an option.

Thanks
Sverre