[R-sig-ME] Specifying a repeated-measure design with 3 fully crossed within-subject factors
Michael Cone
coanil at posteo.org
Tue Aug 12 04:46:28 CEST 2014
Dear list,
I'm trying to specify the appropriate random effects structure for a
repeated-measure design with multiple, fully crossed within-subject
factors.
F1, F2 & F3 are fully crossed factors, repeated several times (> 100,
but not fully balanced) for each subject (each subject saw each unique
combination of F1xF2xF3 several times, order not important). Subjects
are nested within sex. F1 has 4 levels, F2 10 levels, and F3 40 levels.
I am interested in F1, F2, F3 and sex as fixed factors, but trying to
account for the massive amount of pseudo-replication within the data
set.
I tried to do my homework, and, for a simple repeated measure on
different subjects characterized by sex, something like
meas ~ 1 + (1 | sex/subject)
would be appropriate. I am having a hard time, though, extending this
to my design, where a repeated measure on a few subjects was repeated
for each combination of factors F1, F2, and F3. Is it simply
meas ~ 1 + (1 | sex/subject) + (1 | F1) + (1 | F2) + (1 | F3)?
I apologize if this is something obvious. I'm new to mixed models &
lmer and wasn't able to find a similar enough example despite quite some
perusing.
Many thanks,
Michael
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