[R-sig-ME] Fitted values in lmer

[Douglas Bates]

On Fri, Mar 14, 2008 at 7:31 AM, Andy Fugard <a.fugard at ed.ac.uk> wrote:

>  Is there any way to get fitted values out of lmer so that any NAs in the
>  predictors/outcome pop out in the correct position?

Yes.

>   From what I can tell, the "fitted" function doesn't have access to
>  missingness in the inputs.

It does not, in its current implementation.  I believe there is
information regarding the pattern of missingness in the model frame
(stored in the "frame" slot of the fitted model) and that can be used
to generate an appropriate fitted response.

Does anyone know exactly how this is done for linear models?  If so,
are you willing to provide a patch to the fitted method for mer
objects?  I can put it on my ToDo list but when the first item on the
list is "finish the book" you almost never get to the second and
subsequent items.