Identifying sentinel events and analyzing the root causes has been a focus of JCAHO since 1996; the first eight alerts were published in 1998. The Commission defines a sentinel event as "any unexpected occurrence involving death or serious physical or psychological injury, or the risk thereof." The health care facility experiencing the sentinel event is expected to complete a thorough root cause analysis, make improvements to the underlying processes, and monitor the effectiveness of the changes. Although the cause of most sentinel events is human error, changes in organizational systems will reduce the likelihood of human error in the future and protect patients from harm when human error does occur. Specific causes of sentinel events and the solutions that hospitals then used successfully to reduce risks are publicized by JCAHO annually. Alerts have included issues as varied as wrong site surgery, restraint deaths, transfusion and medication errors and patient abductions.