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RegisterReplicate Designs & IntraSubj CV [General Statistics]
Hello all,
I have a 3 period, 2 treatment XO design and would like to calculate the intra-subject CV for the two treatments.
According to FDA guidance, I should use the following SAS code:
however I see my colleagues are using the following:
and I am finding the intra-subject CV's are quite different. I am a little confused regarding which RANDOM statement to use. Can anyone explain the differences and which statement is best to use?
My colleagues also included a carryover in the model but I believe the washout periods are long enough hence not required.
Thanks,
RB
I have a 3 period, 2 treatment XO design and would like to calculate the intra-subject CV for the two treatments.
According to FDA guidance, I should use the following SAS code:
PROC MIXED DATA= cmax ;
CLASSES armcd usubjid period treat ;
MODEL LOG_PARM = armcd period treat / DDFM=KR;
RANDOM treat/TYPE=FA0(2) SUB=usubjid G;
REPEATED/GRP=treat SUB=usubjid;
ESTIMATE 'B vs A' treat -1 1/CL ALPHA=0.1;
LSMEANS treat/ cl alpha=0.1;
RUN;however I see my colleagues are using the following:
PROC MIXED DATA= cmax ;
CLASS USUBJID period treat ARMCD ;
MODEL LOG_PARM = treat period ARMCD /ddfm=KR;
RANDOM USUBJID(ARMCD) ;
REPEATED/GRP=treat SUB=usubjid ;
ESTIMATE "B vs A" TREAT -1 1 /cl alpha=0.1;
LSMEANS treat/ cl alpha=0.1;
RUN;and I am finding the intra-subject CV's are quite different. I am a little confused regarding which RANDOM statement to use. Can anyone explain the differences and which statement is best to use?
My colleagues also included a carryover in the model but I believe the washout periods are long enough hence not required.
Thanks,
RB
Complete thread:
- Replicate Designs & IntraSubj CVrandombadger 2011-04-28 13:02 [General Statistics]
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Replicate Designs & IntraSubj CV Helmut 2011-04-28 15:00
- Replicate Designs & IntraSubj CV randombadger 2011-04-28 15:25
- Replicate Designs & IntraSubj CV Helmut 2011-04-28 17:09
- Inter-subject dance with the wolves d_labes 2011-04-29 11:33
- How many subjects? jdetlor 2011-05-02 18:21
- G matrix d_labes 2011-05-03 08:26
- G matrix ElMaestro 2011-05-03 09:15
- G matrix d_labes 2011-05-03 09:51
- Results randombadger 2011-05-03 12:03
- Results - comments d_labes 2011-05-03 14:32
- Results - comments randombadger 2011-05-03 16:53
- Lost cents d_labes 2011-05-04 08:07
- Results - comments randombadger 2011-05-03 16:53
- Results - comments d_labes 2011-05-03 14:32
- G matrix ElMaestro 2011-05-03 14:16
- Results randombadger 2011-05-03 12:03
- G matrix d_labes 2011-05-03 09:51
- G matrix jdetlor 2011-05-03 19:37
- G matrix ElMaestro 2011-05-03 09:15
- G matrix d_labes 2011-05-03 08:26
- How many subjects? jdetlor 2011-05-02 18:21
- Replicate Designs & IntraSubj CV randombadger 2011-04-28 15:25
- Replicate Designs & IntraSubj CV Helmut 2011-04-28 15:00
Ing. Helmut Schütz