Writing centers seek to expand their services beyond tutoring and develop evidence-based practices. Continuing and expanding the existing practices, the authors have adopted graduate writing groups (GWGs) to support graduate writers, especially those working on independent writing projects like a dissertation or article for publication. This article provides an effective model on how to develop and assess virtual graduate writing groups (VGWGs). This replicable, aggregable, and data-supported (RAD) research applied a mixed-methods design with pre- and postsurveys over the three semesters of running the VGWG. It found that the VGWG offered a full range of writing support that met graduate writers' needs for time-based, skill-based, draft-based, and emotion-based support. Specifically, the VGWG significantly improved students' approaches to writing in five key areas--goal setting, focusing on dissertation writing, generating plans for writing sessions, writing productivity, and writing progress. Therefore, this study contributes robust empirical validation of this model, suggesting that VGWG is an effective method to support graduate writers and expand writing center services. Also, the authors provide a useful model on how writing centers can effectively assess through pre- and postsurveys in a straightforward manner, an assessment model that has both internal and external benefits.