[R] Crossed Random Effects ?

[Douglas Bates]

"Wilhelm B. Kloke" <wb at arb-phys.uni-dortmund.de> writes:

> I have been asked how to handle the following situation in R:
> 
> Given an unbalanced design of 3 crossed random effects, such as
> subject, rater and item, how to estimate the variance components?
> 
> I know how to do it using lme, but this seems to be limited to
> the nested case; or to use aov with error strata, when the
> design is balanced. 

With the current version of lme it is difficult and inefficient to
work with crossed random effects.  A new version of lme being
developed makes this much easier.  I expect to release new versions of
the Matrix and lme4 packages with R-1.9.0 (early April). I will
describe the new lme capabilities in more detail at the useR!2004
conference in May.
-- 
Douglas Bates                            bates at stat.wisc.edu
Statistics Department                    608/262-2598
University of Wisconsin - Madison        http://www.stat.wisc.edu/~bates/