How do you define “taught by grad TAs”?
Do you mean:
- Courses where the primary instructor is a graduate student TA?
- Courses where the primary instructor is a faculty member, but discussion/recitation and/or lab sections are with graduate student TAs?
- A fraction of courses where the primary instructor is a faculty member, but discussion/recitation and/or lab sections are with graduate student TAs, based on the fraction of class hours with the TA in the course?
Case 1 is likely only common in courses like beginning foreign language, frosh-level English composition, and sometimes lower level math. Case 2/3 are quite common at research universities, particularly in lower level courses.
But also, if you are concerned about “transient” instructors, you may also want to know how adjunct faculty are used. Use of adjunct faculty in specialty electives where a non-academic perspective is desirable may be seen differently from the use of adjunct faculty in core courses for one’s major.