Ruth’s PhD is exploring whether using new educational technologies, such as online simulation, can improve the teaching of clinical reasoning skills for medical students. Ruth, along with her supervisors and medical experts has developed an electronic clinical reasoning educational simulation tool (eCREST). ECREST shows patients in general practice, all patients presenting with vague, non-specific respiratory symptoms, which could be indicative of serious conditions that are often missed in primary, such as lung cancer. This will allow students to practise gathering information from a patient, interpret that information and make informed decisions on diagnosis and management. Ruth is currently conducting a feasibility randomised controlled trial at three medical schools, to see whether it can improve clinical reasoning skills, and a qualitative think aloud interview study, to explore how eCREST can help students to learn clinical reasoning skills. This PhD aims to improve future doctors’ awareness of the presentation of potentially serious conditions, such as lung cancer in primary care, to help reduce future diagnostic errors.