<p>At the university where I was in graduate school, my department (the math department) actually employed pretty many UNDERGRADUATE teaching assistants in addition to the graduate teaching assistants. Some of them really did not have sufficient grasp of the material. This was all in violation of the university’s contract with the graduate student employees’ union, which stated among other things that undergraduates were not to be in positions where they were responsible for grading. But it went on because it was such a money-saver. Instead of paying these students for their work, the university gave them course credits for their first semester of being a teaching assistant, as if they were taking a class. I’m not sure whether the students actually had to PAY for the credits, but, man, what a scam. </p>
<p>Also, at least at universities and especially in the sciences and related fields, postdocs are a significant category of people who are neither adjuncts nor ladder faculty. For example, my husband is on his second 3-year postdoc now and is expecting to apply for tenure-track jobs after this ends. Postdocs are hired for a limited period of time, but they are treated better than adjuncts and they definitely have to do research because most of them are hoping to get a tenure-track position afterwards.</p>