At college presentations, it is often said that "our courses are taught by professors" (rather than graduate students), but according to a study at a Dutch business school, it makes little difference. The difference in pay between tenure-track professors and graduate students and adjuncts is vast, and substituting cheaper labor is good for students only if some of the cost savings is passed on, which does not seem to happen.

The Better Teacher: A Professor or Another Student?
by Shannon Watkins
James G. Martin Center for Academic Renewal
SEP 6, 2019