There is an increasing demand for interventions to improve patient safety, but there is limited data to guide such reform. In particular, because much of the existing research is outcome-driven, we have a limited understanding of the factors and process variations that influence safety in the operating room. In this article, we start with an overview of safety terminology, suggesting a model that emphasizes "safety" rather than "error" and that can encompass the spectrum of events occurring in the operating room. Next, we provide an introduction to techniques that can be used to understand safety at the point of care and we review the data that exists relating such studies to improved outcomes. Future work in this area will need to prospectively study the processes and factors that impact patient safety and vulnerability in the operating room.