In this paper we present a phenomenographic analysis of computer science instructors' perceptions of student success. The factors instructors believe influence student success fell into five categories which were related to: 1) the subject being taught, 2) intrinsic characteristics of the student, 3) student background, 4) student attitudes and behaviour and 5) instructor influence on student development. These categories provide insights not only into how instructors perceive students, but also how they perceive their own roles in the learning process. We found significant overlap between these qualitative results, obtained through analysis of semi-structured interviews, and the vast body of quantitative research on factors predicting student success. Studying faculty rather than students provides an alternative way to examine these questions, and using qualitative methods may provide a richer understanding of student success factors.