This study examines the association between three outcomes of the freshman and sophomore years (retention, academic achievement and student rating of instruction) and the amount of exposure to three types of instructors (regular full-time faculty, adjunct faculty and graduate teaching assistants). The growing reliance in higher education on instructors who are not part of the permanent, full-time workforce that has traditionally constituted the professoriate is well documented. Since 1981, the number of part-time faculty employed by colleges and universities has grown by 79 percent, while the share of faculty hired on the traditional tenure track has grown at a much lower rate (Anderson, 2002). According to a report by the Coalition on the Academic Workforce (as cited in Cox, 2000) non-tenure track faculty make up almost half of the teaching staff in many humanities & social science disciplines. Generally, studies have focused on the direct relationships between exposure to adjunct faculty and student outcomes, without taking into effect the background characteristics and other enrollment experiences that may affect these outcomes. The present study attempts to remedy that knowledge gap by modeling student outcomes as a function of exposure to different instructor types while controlling first for variables known to be associated with these outcomes. In this study, part-time faculty will be referred to as "adjuncts." Adjuncts' employment may be long or short-term, but is paid on a part-time contract outside of the regular faculty pay plan. Full-time instructors and lecturers on multi-year contracts but not on tenure-earning lines are included here with the regular, full-time "faculty members."