Sorry to disagree, but personally, I think GLMMOD does not provide a good solution, although it can certainly work. You will understand my biases as you read further. GLMMOD was simply designed to provide some mechanism to output to a data set the same coding that GLM uses. There is no built-in correspondence between the columns in the matrix and the rows when there are BY variables, and there is nothing descriptive in the column names. The test below illustrates.
Transreg was designed to enable various types of coding and provide sensible names and labels along with several options that provide user control over the names and labels. Unlike GLMMOD, a variable always means the same thing throughout the data set.
Much later, when various forms of coding were added to other modeling procedures, they followed the lead of transreg (although not the syntax of transreg), but went beyond what transreg did in many ways. Different variable naming and labeling "cults" were provided as options (although they were never referred to that way outside of SAS).
When I learned linear models in graduate school in the early 1980s at UNC from Ron Helms, there was no automatic way in SAS to get alternative codings (reference cell, LTFR, cell mean, effects, splines, separate slopes and intercepts, separate slopes same intercept, multiple parallel lines, etc.) into a data set. I made providing those codings a priority when I wrote transreg starting in the mid 1980s. I also made transreg handle some esoteric codings common in discrete choice modeling. As I said, now other procs go way beyond what I did in transreg, but GLMMOD is not one of them.
Sorry for the history lesson, but I figure someone out there might find this SAS modeling history interesting.
%mktex(3 ** 6, n=18, out=d1)
%mktex(2 ** 6, n=12, out=d2)
data x;
set d1 d2(in=i);
by = i;
y = _n_;
run;
proc print; run;
proc glmmod data=x outdesign=g1(drop=y) noprint;
class x1-x6;
model y = x1-x6;
run;
proc glmmod data=x outdesign=g2(drop=by y) noprint;
class x1-x6;
model y = x1-x6;
by by;
run;
proc compare error note briefsummary criterion=1e-10
data=g1 compare=g2 method=relative(1);
run;
proc print data=g1; run;
proc print data=g2; run;
proc contents varnum; ods select position; run;
proc transreg data=x design replace;
model class(x1-x6);
output out=t1(drop=_:);
run;
proc transreg data=x design replace;
model class(x1-x6);
output out=t2(drop=_: by);
by by;
run;
proc compare error note briefsummary criterion=1e-10
data=t1 compare=t2 method=relative(1);
run;
proc print data=t1; run;
proc print data=t2; run;
proc contents varnum; ods select position; run;
