Although research on teachers’ comments on student papers is fairly common and has remained an ongoing area of interest since at least the 1970s, composition studies has not yet investigated how teachers’ commenting beliefs and practices change over time, particularly graduate teaching assistants’ (GTAs’) commenting practices. GTAs are an important subgroup of composition instructors to study because not only do they teach a considerable number of first-year composition (FYC) classes across the country, they are also the future of the profession. This dissertation reports the results of a mixed-methods longitudinal study of novice GTAs’ commenting beliefs (i.e., goals, perceived strengths and weaknesses) and practices across their first two years of teaching FYC classes at a large, land-grant university. This research also examines the connections between GTAs’ beliefs and practices and their programs of study and experiences with writing pedagogy education (WPE).

The results of this study indicate that GTAs’ comments do undergo some change, and this change is effected by the GTAs’ time spent teaching, recent WPE experiences, degree programs, and areas of study. However, in nearly all cases, the effect that these variables have on GTAs’ comments is small. In addition, interviews with GTAs reveal that their self–reported commenting goals, strengths, and weaknesses also change over time. GTAs who had acceptable or positive experiences as students and/or teachers that conflicted with their perceived commenting expectations developed some resistance to these expectations, especially after their first semester of teaching. Over time, GTAs also moved from being doubtful of their credibility to more assured, from being concerned with their students’ emotional reactions to their own emotions, and from emphasizing the content of their comments to valuing the ways in which they were writing the comments. These results indicate that more formal WPE may have an impact on GTAs’ teaching practices and should include a focus on the emotional labor connected to teaching writing.