You should make sure to have a balanced design (ie, approx the same pats and cons at each site). Then include site as a regressor, ie, if you had two groups and two sites, you would have four regressors. You could then test for the effect of group, the effect of site, and the interaction. If there is an interaction, then it is hard to interpret the differences between groups.
On 05/08/2017 01:24 PM, Laura Ferrero Montes wrote:
Dear FS team, In case I have data from different centers and I would like to do a group analysis between Patients and Controls, how different centers effects could be regressed out? Should I have to analyze if there is an interaction between center and group? I have seen examples of continuous variables and groups but not in the case of categorical ones. Thank you, Laura _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer