The current healthcare environment is a complex system of patients, procedures, and equipment that strives to deliver safe and effective medical care. High fidelity simulation provides healthcare educators with a tool to create safety conscious practitioners utilizing an environment that replicates practice without risk to patients. Using HFS learning opportunities to refine a learner's clinical decision-making skills under time pressure and high stakes outcomes could provide new opportunities for training the healthcare workforce of the future. This design based research project explored how to structure HFS training to facilitate the development of decision-making in second semester Registered Nursing learners. Borrowing from the research base of aviation and the military, a framework of Situation Awareness was used to define decision-making skills. Using a naturalistic decision-making approach, the research sought to understand how the design of the HFS learning event impacted the ability of participants to demonstrate behaviors of Situation Awareness. Findings of this study demonstrated that design based research is a powerful tool to create a rich understanding of the high fidelity simulation learning experience. The results also supported the work of Jeffries (2005) reiterating that HFS simulation design must be created using strong pedagogical principles that support specific learning outcomes. Particular attention should be focused on maintenance of fidelity, understanding complexity and scaffolding learning opportunities through a multi-phased approach that minimally includes debriefing. The research related to this small group suggests that the briefing stage of HFS learning should be further explored for its influence on learning in HFS. The influence of the facilitator/faculty on the HFS was emphasized in this research suggesting that faculty development would be important for use of this new tool. Additional implications of the research suggest that high fidelity simulation has a role in team training and development of communication skills. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]