Dear Freesurfer Developers,

I'd like to do a standard CT analysis (patients vs. controls, covaried 
for age and sex) on data from a multi-centre study and I'm wondering how 
I should construct my FSGD file to code centre as a dummy variable. 
Currently, my FSGD looks something like this:
GroupDescriptorFile 1
Group Control_Male
Group Control_Female
Group Patient_Male
Group Patient_Female
Variables                               Age
Input   subj001-002     Patient_Male    32
Input   subj001-003     Patient_Male    19
Input   subj001-040     Patient_Female  28
To include centre as dummy variable, would I add an additional column 
for each centre and enter either a 1 or a 0 depending on whether that 
scan is from that centre? For instance, there were 6 centres (scans for 
patients and controls collected at each) in the study, so centre as a 
dummy variable might look something like this (columns added on after 
0 0 1 0 0 0
0 0 0 1 0 0
1 0 0 0 0 0
Moreover, would this be the best way to control for centre?

Many thanks,

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