[R] Missing data and LME models and diagnostic plots

Peter Flom peterflomconsulting at mindspring.com
Wed Oct 21 22:46:28 CEST 2009

I wrote

>>> I am puzzled by the performance of LME in situations where there are
>>> missing data.  As I 
>>> understand it, one of the strengths of this sort of model is how well it
>>> deals with missing 
>>> data, yet lme requires nonmissing data. 

Mark Difford replied

>You are confusing missing data with an unbalanced design. A strengths of LME
>is that it copes with the latter, which aov() does not.

Thanks for your reply, but I don't believe I am confused with respect to missing data in mixed models.  See e.g. Hedeker and Gibbons, Longitudinal Data Analysis, which repeatedly stresses that mixed models provide good estimates if the data are missing at random.



Peter L. Flom, PhD
Statistical Consultant
Website: www DOT peterflomconsulting DOT com
Writing; http://www.associatedcontent.com/user/582880/peter_flom.html
Twitter:   @peterflom

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