[R] Type III sum of squares and appropriate contrasts

[Menelaos Stavrinides]

I am running a two-way anova with Type III sums of squares and would
like to be able to understand what the different SS mean when I use
different contrasts, e.g. treatment contrasts vs helmert contrasts. I
have read John Fox's "An R and S-Plus Companion to Applied Regression"
approach -p. 140- suggesting that treatment contrasts do not usually
result in meaningful results with Type III SS but it's not clear to me
why. Any suggestions on a stats text discussing this would be greatly
appreciated.
Thanks,
Mel

-- 
Menelaos Stavrinides
Ph.D. Candidate
Environmental Science, Policy and Management
137 Mulford Hall MC #3114
University of California
Berkeley, CA 94720-3114 USA
Tel: 510 717 5249