Hi Douglas,
Thanks for your response. I just wanted to confirm how the FSGD and
contrast files might look for the multicentre study. If I'm to create a
separate class for each combination of diagnosis, sex, and center, would
there then be 24 classes? (as there are 2 diagnoses (patient vs.
control), 2 sex, and 6 centres).
For instance:
GroupDescriptorFile 1
Group control_Male_centre1
Group control_Female_centre1
Group control_Male_centre2
Group control_Female_centre2
Group control_Male_centre3
Group control_Female_centre3
Group control_Male_centre4
Group control_Female_centre4
Group control_Male_centre5
Group control_Female_centre5
Group control_Male_centre6
Group control_Female_centre6
Group patient_Male_centre1
Group patient_Female_centre1
Group patient_Male_centre2
Group patient_Female_centre2
...
Then, my contrast between patients and controls would look like
1 1 1 1 1 1 1 1 1 1 1 1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 0
for a doss model, if I'm additionally controlling for age, or 24 zeros
(instead of 1) for a dods model?
Moreover, should I expect any issues with using such a high number of
classes?
Thanks again,
Colleen