Simulation is the imitation or representation of one act or system by another. Healthcare simulations can be said to have four main purposes- education, assessment, research, and health system integration in facilitating patient safety. Each of these purposes may be met by some combination of role play, low and high tech tools, and a variety of settings from tabletop sessions to a realistic full mission environment. Simulations may also add to our understanding of human behavior in the true–to–life settings in which professionals operate. The link that ties together all these activities is the act of imitating or representing some situation or process from the simple to the very complex. Healthcare simulation is a range of activities that share a broad, similar purpose – to improve the safety, effectiveness, and efficiency of healthcare services.