Many graduate medical education programs have instituted patient safety didactics or online courses to meet accreditation standards, but these are likely insufficient in the face of real-world practices commonly witnessed by trainees in clinical settings. Recognizing the importance of this hidden curriculum on shaping trainees' behaviors, the Accreditation Council for Graduate Medical Education (ACGME) created the Clinical Learning Environment Review (CLER) program to evaluate teaching institutions in six focus areas: patient safety, quality improvement, transitions in care, supervision, duty hours, and professionalism. Between June 2017-February 2020, the ACGME visited more than 566 ACGME-accredited institutions as part of this program. According to ACGME leaders, the early findings show an overall lack of trainee engagement in the systems-based practices. Available on the Web site, the latest CLER report describes discoveries from the program and provides a guide for teaching institutions to create clinical environments that support patient safety training and practices.