A consulting firm was hired to discover causes of medication errors for a healthcare facility.

A Pareto chart is the best way to display results when the goal is to communicate the most common causes of medication errors and prioritize improvement actions. In medication safety and quality management, error causes are usually categorized (e.g., wrong dose, wrong patient, transcription issues, look-alike/sound-alike drugs, override of alerts, labeling problems). A Pareto chart sorts these categories from highest to lowest frequency and typically includes a cumulative percentage line, making it easy to see which “vital few” causes account for the majority of errors. This aligns with the Pareto principle (often described as 80/20), supporting leadership decisions about where interventions will yield the greatest impact (training, workflow redesign, decision support tuning, barcode scanning compliance, etc.).

A control chart is designed to monitor a process over time and distinguish common-cause from special-cause variation; it is excellent for tracking monthly error rates but not for ranking causes. A flowchart maps steps in a process and helps identify where errors might occur, but it does not summarize analyzed frequency results. A histogram shows the distribution of numeric data (e.g., time-to-administer), not categorical root-cause frequencies. Therefore, the Pareto chart best displays the analysis of error causes.