[R] typeIII SS for lme?

[Prof Brian Ripley]

On Thu, 11 Dec 2003, Bill Shipley wrote:

> To avoid angry replies, let me first say that I know that the use of
> Type III sums of squares is controversial, and that some statisticians
> recommend instead that significance be judged using the non-marginal
> terms in the ANOVA.  However, given that type III SS is also demanded by
> some
  is there a function (equivalent to drop1 for lm) to obtain type
> III sums of squares for mixed models using the lme function?

I don't think you want SSq for a non-least-squares fit.
Changes in AIC are computed by dropterm() in MASS for lme fits (and 
possibly also by drop1: I have not checked).

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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