This document discusses simulation in medical education. It defines simulation as presenting problems authentically to allow trainees to respond as they would in real situations while receiving feedback. Simulation provides controlled, safe practice opportunities and helps develop clinical skills. Factors driving increased simulation use include problems with clinical teaching, new medical technologies, assessing competence, improving patient safety, and enabling deliberate practice. Effective simulation provides feedback, repetitive practice of varying difficulty, integration into the curriculum, and clearly defined learning outcomes.