That looks right to me. If you use a DOSS model and have a lot of subjects, I don't think there should be a problem with so many classes.
On 04/09/2018 09:50 AM, C.P.E. Rollins wrote:
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
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