What initiatives have accreditation organizations and other external agencies undertaken

Since the Institute of Medicine (IOM), which is now part of the National Academy of Medicine (NAM), published To Err Is Human in 1999, a groundbreaking report that boldly pointed out the problem of medical errors, concerns regarding patient safety and the need to reduce errors have come to the forefront of the U.S. healthcare system.
What initiatives have accreditation organizations and other external agencies undertaken to address these issues? What strategies have been used by ancillary healthcare institutions (mental health and public health) to reduce medical errors? Do you think these efforts have been effective?