Forum .LRN Q&A: Re: Teaching/Course Assitant and Course Administrator roles
All these roles have the same privileges, but correspond to the roles within the real class. The pretty name for these roles titles can be changed on a per-group basis through the group control panel. Also, course administrators display on the members portlet, but not in the staff list portlet.
I thought that they haven't the same privileges, but now it is clear that TA, CA and CAdmin are just synonyms with corresponding roles within the real class.