This document discusses quality issues related to patient safety, specifically medication errors. It defines key terms like medical error, adverse event, and near miss. It then identifies systems and personnel issues that can contribute to medication errors, such as staffing levels, the physical environment, and a lack of adherence to policies and procedures. The document also outlines the nurse's role in preventing errors and systems that have been implemented, such as computerized order entry and barcoding. It provides an overview of a trigger tool for measuring adverse drug events and discusses the results of a previous study on using clinical decision support systems to change physician ordering behavior and reduce errors.