Hello,

Thanks for all the great work done with the SDM project.

I was simply wondering whether SDM controls for the number of studies or coordinates so that it is ok that compare a group of coordinates based on 40 studies (1400 coordinates) versus a group of 12 studies (360 coordinates) ?

Or should we make sure that in our contrast we have roughly the same number of studies, subjects, or coordinates in both compared groups ?

Thanks a lot !

It is Ok. Note that SDM is based on the general linear model and thus this test is conceptually similar to conduct a t-test between two samples.

PS: Note that you are not comparing groups of coordinates but populations of studies.  ;-)