Dear Julian,

Generally effect sizes in REX displays correspond to contrast values, or linear combinations of regressor coefficients, from your secod-level general linear model. For your analyses, looking at patient-control differences in connectivity, those effect sizes (approximately 0.05 in your results)  will be interpretable as average differences in Fisher-transformed correlation values between the patients and control groups. If you prefer to report Cohen's d, in your case that can be easily computed from your analysis T-stats and dofs as d = T / sqrt(dof) (e.g. T=4.11 and dof probably 54 or 52, not totally sure, so Cohen's d in this case is going to be around 0.5 or a "medium-size" effect)

Hope this helps
Alfonso
Originally posted by Julian Roessler: