Abstract
This study builds on extant replicable, aggregable, and data-supported (RAD) research to posit and examine correlations between writing center intervention and improved student writing. The authors review three decades of quantitative writing center scholarship and provide data resulting from four writing center assessments. These assessments include two pre-and post-intervention studies and two intervention/ non-intervention studies. Results are mixed. The pre-and post-intervention studies show statistically significant improvements in student writing. The intervention/non-intervention studies show considerable to limited improvements in student writing. Possible reasons for these results are discussed, including study protocols, self-selection bias, and the difficulty of imposing controls. Impacts on the practice of one writing center are shared, and suggestions for further research are provided.