What Works Clearinghouse^TM (WWC) reviews are designed to provide education practitioners and policymakers with timely and objective assessments of the quality of research evidence. WWC reviews focus primarily on studies of the effectiveness of education or school-based interventions serving students in early childhood education through 12th grade, as well as students in postsecondary settings. However, in some instances, they might focus on studies of interventions serving other groups, such as teachers or other school leaders.

All WWC reviews are governed by a review protocol that describes the procedures that will be followed when conducting the review. When a study has been identified through a literature search defined by a WWC protocol, such as a topic area protocol for preparing WWC intervention reports or a protocol for preparing a WWC practice guide, the study review is guided by that protocol. However, the WWC also reviews studies that have been identified through other means and that may not fall under the umbrella of a more specific review protocol. The version 3.1 and 4.0 protocols guide such reviews of individual studies. These review-specific protocols are used in conjunction with version 3.0 and version 4.0 of the WWC Procedures and Standards Handbooks, respectively.