Benjamin (2002) has suggested ways that overreliance on part-time faculty may undermine successful student integration. Not only did he find part-time faculty to be relatively unavailable, but he also found that many used less challenging instructional methods. Plausibly, then, reliance on part-time faculty may hinder both social and academic integration and may also be understood as a factor that connects the integration model to the Bean and Metzner barrier or “student attrition” model.
New Directions for Higher Education published a dedicated volume documenting concerns that poor institutional assimilation by part-time faculty adversely affects student learning. The effects included reduced instructional quality, lack of curricular cohesion, and weak advising (Benjamin, 2003a, 2003b; Cross & Goldenberg, 2003; Elman, 2003; Schuster, 2003; Thompson, 2003; Townsend, 2003). While successfully raising questions about the instructional effectiveness of part-time faculty, the quantitative evidence in that volume did not address the central question of whether heavy reliance on part-time faculty significantly alters student outcomes. This issue was directly assessed in two quantitative studies examining student persistence and graduation. Harrington and Schibik (2001) studied one large midwestern university and found that, when freshmen took a higher percentage of their courses with part-time faculty, they were less likely to persist towards their degree. Ehrenberg and Zhang (2004) tested a large sample of institutions for which there were multiple observations dating back to 1986. They concluded that for each 10% increase in the percentage of faculty employed part-time at four-year institutions, graduation rates decrease by 2.65%.