Hi Harriet,

Yes, there are a couple of ways to do this:

1) create new second-level covariates that have the same values as your original ones except that they have zeros for the subjects that you want to exclude, then simply use these new covariates in your second-level analyses. By default CONN will exclude from a second-level analysis any subject where *all* of the selected between-subject effects are zero (this is the same strategy used, for example, when you want to perform within-group second-level analyses)

or 2) create a new second-level covariate for each subject you want to exclude (dummy coded, 1 for the excluded subject and 0 for everyone else; one covariate for each excluded subject - not all excluded subjects in a single covariate). Then simply include these new covariates in any analysis where you want to exclude some subjects).

Both approaches are exactly equivalent, and they will produce the exact same results.  For "sanity-checking" look at the degrees of freedom of the results, they should always be equal to the number of subjects included in your analyses minus the number of between-subject effects included in the analyses.

Hope this helps
Alfonso


Originally posted by Harriet Johnston: