Abstract
Diagnostic error represents an important patient safety issue. Herein, we summarize five important things to know about this topic. 1) At least 1 in 20 adults are affected by diagnostic errors annually. 2) The root causes for diagnostic errors are typically multifactorial. 3) Cognitive errors are found in the majority of cases. 4) Most missed diagnoses involve common conditions. 5) Advancements in policy, education, and health information technologies hold promise for improving diagnostic safety.