<p>OP-
Specific to USC: D is a rising soph at USC and had several of the largest science classes last year. About 200 in the class with small (less than 20) in the labs. Classes taught by profs and labs by TAs. TAs graded lab work and probably class tests. However, in her GE classes were much smaller-- 20-30 people and no TAs involved. Profs both graded ALL work themselves in these small classes. D felt comfortable visiting both prof and TA office hours. </p>
<p>General about U TAs-- At any U with graduate students you should expect TAs to be involved in the education process, either by grading, teaching discussions or lab sections, or the occasional lecture. That is how they are subsidizing their education. At many Us grad students do a considerable amount of the summer teaching as lecturers. They all have to start somewhere and the summer is usually the place. </p>
<p>You will need to decide for yourself if you need a prof involved in all educational experiences or if a TA would be fine for some things.</p>