Research synthesis has been widely applied in Data-Driven Learning (DDL) and will continue to play an important role as research progresses within CALL. This entry provides an overview of research synthesis in DDL, with a review of several key research syntheses. The entry explains how research synthesis is used in DDL for evidence evaluation, summarisation, critical appraisal and articulating the scope of research in the field. The most common synthesis research designs are outlined, guiding readers through the methods, motivations and findings of selected studies that illustrate best practice and point toward areas for future research synthesis.