A Systematic Review of Spaced Repetition, Retrieval Practice, and Academic Performance in Undergraduate Medical Students.

Spaced repetition and active retrieval practice are learning strategies designed to improve long-term memory retention. These approaches target the forgetting curve, which describes the progressive loss of information over time unless learners actively recall and review material at spaced intervals. Modern learning platforms such as Anki and Quizlet use scheduled review and retrieval to strengthen memory consolidation and recall, and their use in undergraduate medical education has increased in recent years. This systematic review aimed to determine whether spaced repetition and active retrieval interventions improve memory retention and examination performance among undergraduate medical students. The review followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, ERIC, and Scopus were searched for studies examining spaced repetition or retrieval practice in undergraduate medical students, and studies reporting objective academic outcomes were included. Of 314 records identified, 210 remained after duplicate removal, and 21 studies met the inclusion criteria. Due to heterogeneity in study designs, interventions, and outcome measures, a narrative synthesis was undertaken, and no meta-analysis was performed. Most controlled studies reported improvements in examination performance or knowledge retention following spaced retrieval interventions. Observational studies of self-directed flashcard use reported mixed findings. Several demonstrated positive associations with academic performance, whereas others, including studies that measured platform use objectively rather than by self-report, found no association. These findings were more susceptible to self-selection bias and confounding, and most were judged to be at serious risk of bias. Several studies suggested greater benefit with sustained and longitudinal engagement. Overall, the available evidence suggests that spaced repetition and active retrieval practice may improve academic outcomes in undergraduate medical education, particularly when implemented longitudinally through structured retrieval. Controlled studies provided stronger support for these benefits, whereas evidence from observational studies of self-directed Anki use was weaker because of potential selection bias and confounding. Future research should focus on standardized implementation strategies and longer follow-up to determine whether early use of spaced retrieval produces durable benefits during clinical training and on future examinations.