Editor's Note: This article is excerpted from The NLN Jeffries Simulation Theory, a monograph published by the National League for Nursing, copyright 2015.Based on the thorough synthesis of the literature by Adamson (see page 282) and discussion among simulation researchers and leaders, the NLN Jeffries Simulation Framework (2005, 2007, 2012) is now referred to as the NLN Jeffries Simulation Theory with a few minor changes within the conceptual illustration. The concepts of this theory are briefly described below to provide more clarity and to explain the new NLN Jeffries Simulation Theory. (See the Figure for a diagram of the theory.)CONTEXTContextual factors such as circumstances and setting impact every aspect of the simulation and are an important starting point in designing or evaluating simulation. The context may include the place (academic vs. practice; in situ vs. lab) and the overarching purpose of the simulation, for example, whether the simulation is for evaluation or instructional purposes.BACKGROUNDWithin this context, the background includes the goal(s) of the simulation and specific expectations or benchmarks that influence the design of the simulation. The theoretical perspective for the specific simulation experience and how the simulation fits within the larger curriculum are all important elements of the background and inform the simulation design and implementation. Finally, the background of a simulation includes resources such as time and equipment, as well as how these resources will be allocated.DESIGNOutside of and preceding the actual simulation experience are specific elements that make up the simulation design. Although some elements of the simulation design may be changed during implementation of the simulation experience, there are aspects of the design that need to be considered in preparation for the simulation experience.The design includes the specific learning objectives that guide the development or selection of activities and scenario(s) with appropriate content and problem-solving complexity. Elements of physical and conceptual fidelity - including decisions about equipment, moulage (physical), and appropriate, predetermined facilitator responses to participants' interventions (conceptual) - are established as part of the simulation design. Participant and observer roles (including whether or not videography will be used), progression of activities, and briefing/debriefing strategies are all established as part of the simulation design.SIMULATION EXPERIENCEThe simulation experience is characterized by an environment that is experiential, interactive, collaborative, and learner centered. This environment requires the establishment of trust; both the facilitator and participant share responsibility for maintaining this environment. They enhance the quality of the simulation experience through buying-in to the authenticity of the experience and suspending disbelief. This helps promote engagement and psychological fidelity within the simulation experience (Kiat, Mei, Nagammal, & Jonnie, 2007; Leighton & Sholl, 2009; van Soeren et al., 2011).FACILITATOR AND EDUCATIONAL STRATEGIESWithin this simulation experience is a dynamic interaction between the facilitator and the participant. The literature about the characteristics these individuals bring to the simulation experience and how they affect the simulation experience is extensive. Facilitator attributes include (but are not limited to) skill, educational techniques, and preparation (Parker & Myrick, 2012; Parsh, 2010). The facilitator responds to emerging participant needs during the simulation experience by adjusting educational strategies such as altering the planned progression and timing of activities and providing appropriate feedback in the form of cues (during) and debriefing (toward the end) of the simulation experience.PARTICIPANTParticipant attributes also affect the simulation learning experience. …