[R] Comparison of SAS & R/Splus

[Thomas Lumley]

On Thu, 4 Sep 2003, Paul, David  A wrote:

> I am one of only 5 or 6 people in my organization making the
> effort to include R/Splus as an analysis tool in everyday work -
> the rest of my colleagues use SAS exclusively.
>
> Today, one of them made the assertion that he believes the
> numerical algorithms in SAS are superior to those in Splus
> and R -- ie, optimization routines are faster in SAS, the SAS
> Institute has teams of excellent numerical analysts that
> ensure its superiority to anything freely available, PROC
> NLMIXED is more flexible than nlme( ) in the sense that it
> allows a much wider array of error structures than can be used
> in R/Splus, &etc.


While I don't subscribe to the general theory, they have a point about
PROC NLMIXED.  It does more accurate calculations for generalised linear
mixed models than are currently available in R/S-PLUS, and for
logistic random effects models the difference can sometimes be large
enought to matter.


	-thomas