Today, nearly forty years after writing centers first began to proliferate, it is worthwhile to reflect on the themes that emerge from empirical material surrounding writing center assessments, for reflecting on these themes may help administrators to refine current assessment practices and scholars to redirect their research. The goal of this essay, then, is to review the literature on assessments of writing centers. Specifically, this paper examines the goals and methodologies associated with this assessment that are reported in writing center literature. The ultimate purpose of this review is to offer readers a sense of what is effective in writing center assessments, what is ineffective, and how future research in this area might be shaped. This paper will also review the limitations that have been identified as precluding extensive assessment within writing centers.