. >> reporter: arik greenberg teaches theology at loyola marymount university. >> reporter: we are not given any kind of benefits. no medical, no dental, no vision, no retirement, no family leave, no sick leave, nothing. >> reporter: to support his family, rob balla drives to three different ohio universities to teach six english classes and tutors on the side. he had pneumonia last fall, worked anyway. >> we go to school under any circumstances really, because you can't afford to have your pay docked. >> reporter: these are adjuncts, part-time professors paid an average of $2,00$3,000 per class with few to no benefits who now make up half of college faculties-- a drastic change from just a few decades ago. >> in 1970, about 80% of the faculty were on the tenure track. >> reporter: but non-tenured faculty have become the rule, says education professor adrianna kezar. >> this trajectory started in community colleges, it spread across four-year institutions and research universities and it's public and private. >> reporter: nicole beth wallenbrock got a ph.d. in french lit to become a fu