In the last 15 years, writing center scholars have increasingly called for more evidence to validate writing centers' practices. Work by Paula Gillespie (2002), Neal Lerner (2009), and Isabelle Thompson et al. (2009) underscore this need. Missing from these discussions, however, is a thorough understanding of the past and current research practices. This article seeks to fill this gap by: (1) tracing a short history of writing center research within the context of methodological changes in the field of rhetoric and composition; (2) conducting a comprehensive analysis of research articles published in "The Writing Center Journal" ("WCJ") from 1980 to 2009 using Richard Haswell's 2005 paradigm for replicable, aggregable, and data-supported (RAD) research; and (3) offering examples of RAD research within "WCJ" and suggestions for producing more RAD research. (Contains 3 figures, 1 table, and 9 notes.)