Aim To design a simulation learning activity with the aim of allowing trainees to recognise and manage a neonate with a pneumothorax using deliberate practice, mastery learning and progressive fidelity. Background The implementation of the Working Time Directive invariably reduced clinical exposure for trainees to conditions that occurred less frequently such as neonatal pneumothoraces. On questioning previous trainees at the end of their neonatal post on our unit on which procedures they would like more training on, chest drain insertion was frequently mentioned. Chest drain insertion on a neonate is not an isolated practical skill. It involves firstly recognising the signs and symptoms of a pneumothorax in a neonate whilst also interpreting X-rays, secondly making decisions about the management of a critically ill patient and thirdly managing a multi-disciplinary team in an often very stressful and time-critical environment. It requires the development of healthcare professional expertise. Method A review of the current literature was undertaken to identify the key features required to ensure an effective design. Mastery learning, deliberate practice and progressive fidelity were identified as features of simulation that led to effective learning.1,2 Further review of the literature was then undertaken to understand the underlying theories and evidence for these concepts. These were then incorporated into the teaching session. Results The final teaching session involved two teaching models, a didactic session focusing on acquiring knowledge and simulation sessions allowing practical application of that knowledge. The scenarios were based on real clinical cases. Critical events were identified that would become the learning outcomes similar to the domain-related activities mentioned in expert practice. To incorporate a mastery-learning model a checklist was produced for each simulation session detailing the minimum standard to be reached. A trainee could not progress to the next simulation session until he/she had reached that standard. The fidelity of the simulation sessions progressed from low to high fidelity as the participants competence improved. Conclusion A teaching session was designed to meet the needs of inexperienced trainees working on a tertiary neonatal unit. All teaching should be based on sound theoretical background and scientific evidence. This approach combined with clinical experience should then ensure that effective simulation teaching is delivered. References . Issenberg, et al. Medical Teacher 2005;27(1):10–28. . Motola, et al. Medical Teacher 2013;35(10):e1511–e1530.