[R] Order of terms in a model specification...

[Oliver Lyttelton]

Hi,

Sorry for this one as its pretty basic but I've taken a look for info and
couldn't find any...

My question is, does the order of main effect terms in a model specification
have any impact on the model R fits or not. (in particular when using lm).
ie

Can A~X+Y+Z lead to different results to A~Z+Y+X, and if so in what
circumstances, and how much should I worry about it?

I believe this is an implementation detail as it depends on the way the
fitting algorithm works, but it would be great to have a few lines to plug
this gap in my knowledge...

Many thanks,

Oliver