Formed in 2008, the Multicenter Perioperative Outcomes Group (MPOG) is a consortium of several medical centers aggregating large volumes of observational inpatient electronic health record (EHR) data and patient-reported outcomes. MPOG has already extracted, transformed, and mapped more than 2 million patient records from various medical centers across the US and Europe. MPOG contains demographic information, basic case information, and pre-, intra- and post-operative documentation, as well as hospital discharge codes and charges. More information regarding MPOG may be found here.