topic What is the meaning of different RESIDUAL positions in the PROC GLIMMIX' RANDOM statement ? in SAS Procedures

What is the meaning of different RESIDUAL positions in the PROC GLIMMIX' RANDOM statement ?

stan — Thu, 22 May 2014 13:19:53 GMT

Folks:

here are the examples:

RANDOM <my_variable1> / RESIDUAL SUBJECT = <my_variable2>;

and

RANDOM _RESIDUAL_ / SUBJECT = <my_variable2>;

Thank you.

Re: What is the meaning of different RESIDUAL positions in the PROC GLIMMIX' RANDOM statement ?

SteveDenham — Fri, 23 May 2014 14:10:13 GMT

The former syntax specifies an R side covariance structure for <my_variable1>, while the latter syntax models an overdispersion. I believe that since the default type is TYPE=VC, the two statements as they currently stand should yield the same results. If not, please post, as this is a potentially interesting event.

Steve Denham

Re: What is the meaning of different RESIDUAL positions in the PROC GLIMMIX' RANDOM statement ?

stan — Mon, 26 May 2014 17:35:34 GMT

Steve, at first glance the outputs are the same. I also met another explanation by @lvm:

If you do not have missing values for trial (i.e., same trials for each subject), you can use:
RANDOM _RESIDUAL_ / SUBJECT=SUB TYPE=CS;

Probably this is the same you mention.