Now available for purchase are AHRQ’s 2015 National Inpatient Sample (NIS) and the 2015 Nationwide Readmissions Database (NRD), premier databases that enable analysis of all-payer hospital inpatient stays and readmissions. Part of the agency’s Healthcare Cost and Utilization Project (HCUP), the databases support efforts by researchers and policymakers to quantify and track national trends broken down by patient characteristics and use of hospital resources. To ensure researchers’ appropriate use of the NIS, AHRQ released a checklist of major methodological considerations. The HCUP family of health care databases and related software tools and products is made possible by a federal-state-industry partnership sponsored by AHRQ. The updated NIS and NRD databases are available from AHRQ’s HCUP Central Distributor.