This guide outlines the IAB/MRC Retail Media Measurement Guidelines, which are designed to establish measurement standards and business requirements for retail media organizations. The document details the collaborative efforts of the IAB Retail Media Measurement Working Group and the Media Rating Council (MRC) in creating a comprehensive framework for measuring retail media effectiveness. It covers various aspects of measurement, including data collection, audience metrics, ad delivery, viewability, and incrementality measurement methodologies. The guidelines emphasize the importance of data accuracy, transparency, and best practices in reporting. Additionally, it addresses the need for clear definitions and methodologies for retail media metrics, ensuring that organizations can effectively track and report on their advertising performance across different platforms. The document serves as a critical resource for both advertisers and publishers in the retail media landscape, aiming to enhance measurement practices and improve overall media accountability.