Also swelling is the number of adjuncts. They now make up 50 to 75 percent of those teaching in higher education. Why colleges rely so much on adjuncts has been discussed thoughtfully and at length elsewhere; chief among the reasons are that they are not as expensive as tenure-track professors, their scheduling can more easily align with the needs of the college, and firing them is not fraught with the same peril as firing full-time faculty members.
It should hardly come as a surprise that all of the factors that make adjuncts attractive to administrators make them equally attractive to union organizers. For example, at Washington University in St. Louis, where adjuncts voted 138 to 111 in favor of organizing, the core issues were low wages, lack of benefits, and lack of job security.