The Veterans Administration has encouraged use of root cause analysis (RCA) as a structured method of analyzing errors in hospitals and clinics. In this article, the authors examine RCAs performed due to medication errors. Structured review of RCAs was combined with interviews with patient safety officers in order to gain a full perspective on the incident, the individual and system factors leading to the error, the proposed solution, and the success (or failure) of the institution's response to the error. Through this "360-degree" analysis, the authors were able to explore which types of system changes were associated with a greater chance of sustained safety improvement. A prior AHRQ WebM&M commentary describes the process of conducting an RCA for a medication error.