How much basic science content do second-year medical students remember from their first year?

While most medical students generally perform well on examinations and pass their courses during the first year, we do not know how much basic science content they retain at the start of their second year and how that relates to minimal competency set by the faculty. In the fall of 2014, before starting their second-year courses, 27 medical students volunteered to participate in a study of long-term retention of the basic sciences by taking a "retention exam" after a delay of 5-11 months. The overall mean performance when the students initially answered the 60 multiple choice questions (MCQs) was 82.8% [standard deviation (SD) = 7.4%], which fell to 50.1% (SD = 12.1%) on the retention exam. This gave a mean retention of 60.4% (SD = 12.8%) with the retention for individual students ranging from 37 to 81%. The majority of students (23/27; 85%) fell below the minimal level of competency to start their second year. Medical educators should be more aware of the significant amount of forgetting that occurs during training and make better use of instructional strategies that promote long-term learning such as retrieval practice, interleaving, and spacing.