Ideally, part-time instructors are—as one example—individuals with good jobs who like to teach and want to share their professional knowledge and experience with students. Or maybe they are retired or semi-retired instructors who taught full-time previously and still enjoy it.
Quite possibly these particular individuals are not interested in a full-time position (though adjunct instruction is an great way to gain teaching experience for recent graduates with advanced degrees).
These are excellent scenarios, and there are plenty of others. Most practitioners believe that part-time instruction is, generally speaking, a good thing for the school and the teachers.
Then there are the teachers profiled in a recent article in the Chronicle of Higher Education by Stacey Patton. Welfare. Food Stamps. Poverty. Please read the article.
The piece reports that the situation is far worse for individuals in the liberal arts and humanities, which have not received the same financial support or policy commitment in core curricula as disciplines in the sciences and technology.
Some commentators, including Dead Dad, in Inside Higher Ed., think we should quit encouraging students to embrace fields offering no realistic hope for gainful employment. This is a tough call, because students often want to emulate their professors in subjects that interest them. Teachers are understandably pleased and often nudge promising students toward this goal.
Then, years later, according to the CHE piece, talented new Ph.D.s find themselves in the abyss, bagging groceries while teaching part-time, trying to pay off student loans.