This document summarizes the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 guidelines for evaluating tumor response in clinical trials. It introduces the three types of oncology studies, defines target and non-target lesions, and describes how lesion measurements are used to determine complete response, partial response, stable disease, progression disease, and not evaluable responses. It also discusses how RECIST 1.1 data are organized in CDISC SDTM and ADaM domains, and provides an example of how these domains can be used to evaluate tumor response and analyze outcomes like objective response rate, progression-free survival, and time to progression.