PROC GENMOD LSMEANS REFERENCE

[superbibi]

Hi SAS users,

My current code only shows the adjust p-values with vis = 30 as the reference group. If I want to use vis = 20 as the reference group, how should I modify the code?

PROC SORT DATA = test ;
BY VIS;
RUN;

PROC GENMOD DATA = test;
CLASS VAL  SUBNUM VIS (REF = "20" )  ;
MODEL VAL =  VIS/DIST = BIN ;
REPEATED SUBJECT = SUBNUM/CORR = UNSTR CORRW;
LSMEANS VIS/PDIFF ADJUST = DUNNETT;
RUN; 

[FreelanceReinh · Accepted solution]

Hi @superbibi,

I think the result from

LSMEANS VIS/PDIFF=control('20') ADJUST = DUNNETT;

looks promising (cf. documentation of the PDIFF option).

[superbibi]

Thank you very much! It works.

[superbibi]

Is there a way to calculate the overall p-value for vis using proc genmod?  In the attached code, I got only the p-values for each paired comparison.

[FreelanceReinh]

Do you mean the Wald chi-square test?

  Wald Statistics For Type 3 GEE Analysis

                          Chi-
Source           DF     Square    Pr > ChiSq

VIS               7      37.94        <.0001

To obtain this, you need to add the TYPE3 and WALD options to the MODEL statement:

MODEL VAL =  VIS/DIST = BIN type3 wald;