Beginning in 2006, Northwestern University Internal Medicine and Emergency Medicine residents completed simulation-based mastery learning in central venous catheter (CVC) insertion before clinical rotations in the Medical Intensive Care Unit (MICU). This comprehensive program in central line training used repetitive practice and simulation technology to train residents to mastery standards. This study had important patient safety implications. This program resulted in improved trainee skill and reduced CVC insertion complications, including a significant decrease in the rate of central line associated bloodstream infections (CLABSI). In addition, the investigators showed that the in CVC insertion was highly cost-effective suggesting that investment in simulation training can produce significant medical care cost savings.