mixed effects logistic regression diagnostics

Hi Stella,
Not sure what you are looking for with "cooks distance" etc

Are you able to provide example of the syntax you are using to specify 
your model? As this could help to get some more specific guidance?
There is a "profile" method for model diagnostics but I'm not sure if 
this is available for the binomial family or which versions of lme4 this 
is currently available in? (The developers work so fast I can never keep 
up).
Chapter 1 of the draft version of the new book by Doug Bates ( 
http://lme4.r-forge.r-project.org/book/ ) has some useful information on 
model diagnostics .......

hth,
Darren