Historically, medical errors were thought to be the result of inadequate knowledge, lapses in vigilance, or lack of competency of individual doctors and nurses. In reality, catastrophic medical errors are very rarely the result of one individual’s failure. Most errors are caused by predictable human failures in the context of poorly designed and increasingly complex healthcare systems. Rather than focusing corrective efforts on individual punishment or expecting a flawless performance from human beings, the systems-based approach to medical errors stresses that exploration of all of the underlying conditions or “root causes” which give rise to human error is needed to reduce the occurrence of errors in the future. In order to do this effectively, leaders must first create a hospital culture of safety; one that encourages trust, teamwork, and open discussion about medical errors so risks can be readily identified and focused improvement work to minimize future errors can begin.