<p>As McGill is a research university, I was wondering how much teaching is done by professors and how much by teaching assistants (grad students)? Does this vary a lot by Faculty and department? Overall, how is the quality of teaching?</p>
<p>TAs don't teach, they do tutorials (that is, possilby mandatory sessions outside of regular lectures where, say in calculus, they do lots of example problems). Graduate student instructors do exist, and tend to teach intro level classes. Numbers vary probably between departments and certainly per semester (that is, you're more likely to get one during the summer semester, for those who wish to take summer classes). And some teach better than many tenured profs. But overall, most teaching is done by profs, even in intro level courses. Quality depends a lot on the prof and expectations of the students (in the sense that if you're expecting lots of personal attention, it's not going to happen, at least by not itself), but overall is high.</p>