Diagnostic error is a significant concept within healthcare quality and patient safety research, defining the failure to establish an accurate and timely explanation of a patient's health problem or to communicate that explanation to the patient. This academic field investigates the cognitive, systemic, and environmental factors contributing to missed, delayed, or incorrect diagnoses, analyzing their impact on patient outcomes and healthcare resource utilization. Its significance lies in identifying root causes, developing mitigation strategies, and improving diagnostic processes to enhance patient safety and reduce preventable harm.