Graduation Year


Document Type




Degree Granting Department

Industrial Engineering

Major Professor

Jose L. Zayas-Castro Ph.D.

Committee Member

Michael T. Brannick, Ph.D.

Committee Member

Robert P. Carnahan, Ph.D.

Committee Member

Kingsley Reeves, Ph.D.

Committee Member

Michael X. Weng, Ph.D.


Graduate Medical Education, Human Error, Medical Error, Patient Safety, Surgical Complications, Surgical Outcomes


The Institute of Medicine report "To Err is Human," released in late 1999, raised the issue of human error in medicine to a new level of attention. This study examines the frequency, severity, and type (FST) of errors associated with postoperative surgical complications at a tertiary care, university-based medical center, addressing the intersection of three domains: patient safety, graduate medical education, and simulation-based training. The study develops and validates a classification system for medical error that is specific to surgery, affirming reliability internally and externally. Baseline data on the FST of errors is collected over a 12-month period. A hybrid, simulation based training session is developed, validated, and applied to a cohort of surgical residents, focusing on the three most common types of errors identified from pilot data, namely judgment error, incomplete understanding of the problem, and inattention to detail, all human factor errors. The impact of the training is evaluated by measuring the FST of errors occurring during the 6-month period following the training sessions. The study demonstrates that there is a continuous decrement in the incidence of postoperative complications and a proportional decrease in error, which starts at the beginning of the baseline data collection and continues linearly throughout the 12 baseline months and subsequent 6 post-training months. There is no additional decrement in the rate of change following training, and no change in the rate of the index errors following the training. This study suggests that surgical error is frequent (>2%) and principally due to human factors rather than systems or communication. This study demonstrates that creating an environment where residents are continuously involved in identifying and characterizing errors results in a significant and sustained decrease in postoperative complications and the errors specifically associated with them. Contrary to expectations, a validated, well-designed, active-learning training module does not result in an additional identifiable improvement in patient outcome or in the incidence of index errors. These results are at variance with many recent studies addressing medical error and, if verified by additional studies, challenge several strongly held ideas related to patient safety training.