Replicable, aggregable, data-supported (RAD) research has become standard in writing center studies. Choice of research question is determined by local conditions and exigencies, often influenced by institutional assessment policy and national mandates. The methodology of choice in most writing center research is qualitative inquiry, though quasi-experimental quantitative studies, with their inherently difficult protocols and ethical problems, persist in their effort to address the question fundamental to writing center labor: Does writing center tutoring improve student writing? In a quasi-experiment applying propensity score matching to a sample of student users of the Rockowitz Writing Center at Hunter College of the City University of New York, this study comprehensively surveys the scholarship and interrogates the local context, argues for the authority of grades and GPAs as outcome measures, and offers results that, considered in aggregate with center lore and quantitative writing center research, infer causality: Yes, we do help students improve their academic writing.