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Registerrandom vs. fixed [Software]
posted by Helmut 
– Vienna, Austria, 2011-10-07 23:35 (5365 d 09:42 ago) – Posting: # 7447
Views: 8,133
Hi Yicaoting & ElMaestro!
Yessir.
Right guess. Phoenix/WinNonlin’s default in BE is:
Therefore we get REML estimates. If we delete the random effect and specify the model as ‘all fixed’
WNL will spit out exactly SAS’ results (LSM_T, SE, Diff, and CI) for dataset 3.
Wasn’t necessary.
❝ ❝ For dataset 3, results from WNL:
❝ ❝ LSM_R: 82.5594 (WNL) vs 82.5594 (SAS)
❝ ❝ LSM_T: 79.6926 (WNL) vs 79.2074 (SAS)
❝ Hrmmmmmmmfff...
Yessir.
❝ However, there is -at least in theory- an alternative when one value is missing for a period in one (or more) subject(s) and that is to try a maximum likelihood approach where you specify subject as random in the mixed model and trt+seq+per all fixed. When I do that in R, I actually can reproduce your values from WNL (but I do not have WNL on my machine so cannot play around). It could thus be that WNL actually uses a mixed model to obtain the estimates?
Right guess. Phoenix/WinNonlin’s default in BE is:
fixed: Sequence+Formulation+Period
Random: Subject(Sequence)Therefore we get REML estimates. If we delete the random effect and specify the model as ‘all fixed’
Sequence+Formulation+Period+Subject(Sequence)WNL will spit out exactly SAS’ results (LSM_T, SE, Diff, and CI) for dataset 3.
❝ Someone, go read the manual?!
Wasn’t necessary.
—
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Helmut Schütz
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Dif-tor heh smusma 🖖🏼 Довге життя Україна!
Helmut Schütz
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Complete thread:
- Least Square Means (LSM) for incomplete data yicaoting 2011-10-07 18:27
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Least Square Means (LSM) for incomplete data ElMaestro 2011-10-07 21:00
- random vs. fixedHelmut 2011-10-07 21:35
- random vs. fixed ElMaestro 2011-10-07 23:18
- random vs. fixed Helmut 2011-10-08 14:48
- random vs. fixed ElMaestro 2011-10-08 15:26
- random vs. fixed Helmut 2011-10-08 16:02
- random vs. fixed ElMaestro 2011-10-08 15:26
- random vs. fixed Helmut 2011-10-08 14:48
- random vs. fixed ElMaestro 2011-10-07 23:18
- random vs. fixedHelmut 2011-10-07 21:35
- Least Square Means (LSM) for incomplete data ElMaestro 2011-10-07 21:00
Ing. Helmut Schütz