Dear List:

 

I was able to run the following in nlme successfully, but the same model
and code (same dataset) failed to run in lme4 and gave me the error
message below. Any thoughts?

 

lme(math~year, data=egsingle, random=~year|schoolid/childid)

 

Error in lme(formula = math ~ year, data = egsingle, random =
structure(list( : 

        Unable to invert singular factor of downdated X'X

 

Harold


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