Hi all,
I am facing a problem with Dunnett`s multiple comparisons test with a reference/control group.
Here is the code :
ods output lsmeans = _tpvalues;
proc glm data=_talldata_wide;
title 'Pair-wise comparison with Dunnett correction';
class _pooled ;
model _L21 _L22 = _pooled ;
lsmeans _pooled /pdiff = control ("0") adjust=Dunnett;
run;
quit;
ods trace off;
_pooled is the variable that contains the dose group codes, but control group coded as 0 than its actual value.
For Eg :
dosegrpc _pooled
------------- ------------
5 0 /*coded as 0 since its Control Group*/
15 15 /* treated group */
50 50 /* treated group */
Now say you have one control group and one treated Group
_pooled
------------
0
15
The above proc glm, produces a P-value against dose_group_code = 0, rather than against 0. This is the problem.
Can anybody suggest what is going wrong here. Your help would be greatly appreciated !
Thanks,
Neeral Beladia