This module introduces you to the famous W. Edwards Deming red bead experiment that illustrates the tyranny of random variation, and introduce the use of run charts to differentiate random or common cause from specific cause variation. Next we will introduce you the concept of reliability and will illustrate why we need to dramatically improve the reliability in health care. Strategies for reducing human errors are reviewed, and the effectiveness hierarchy of different interventions discussed. We end with a discussion of how health systems and providers should be treating patients and families who they have inadvertently harmed.