Commercial scanner data on retail food purchases are an integral resource for a broad range of food policy research. ERS has acquired proprietary household and retail scanner data from IRI, a market research firm, including novel data on nutrition information and health and wellness claims for a large number of products. This report provides a detailed description of the methodology, characteristics, and statistical properties of these datasets and summarizes the limitations and considerations for using these data for food economics research. The report shows that the IRI data are an extensive, complex data source and provides an introduction to the data for new users and important considerations for advanced users.