Basically, I used the without intercept to get an estimate for each of my
factor levels instead of using a reference class. So I use a kind of hidden
intercept.
I should have noticed that the behavior was documented in ?summary.lm.
Sorry for the inconvenience.
Lieven
Duncan Murdoch-2 wrote
Full_Name: lieven clement
Version: R version 2.4.0 Patched (2006-11-25 r39997)
OS: i486-pc-linux-gnu
Submission from: (NULL) (157.193.193.180)
summary.lm() does not calculate R² accurately for models without intercepts if
one of the predictor variables is a factor.
In order to avoid one of the
