This document provides step-by-step instructions on how to complete the Study Review Guide (SRG, Version S3, V2) for single-case designs (SCDs). Reviewers will complete an SRG for every What Works Clearinghouse (WWC) review. A completed SRG should be a reviewer's independent assessment of the study, relative to the criteria specified in the review protocol and the WWC Procedures and Standards Handbook (Handbook). At the end of the review process, a Master SRG (MRG) will represent the final assessment of the study, provide a record for the WWC, and serve as a key input in producing reports. This guide is intended to be used by people trained and certified in the WWC pilot SCD review standards and procedures and in conjunction with the WWC Handbook.