Learning curves graphically represent the relationship between learning effort and learning outcome. Learning curves are increasingly used in research, the design of randomised controlled trials, the assessment of competency, healthcare education and training programme design. In this review we have outlined the principles behind plotting learning curves, described the common methods used to analyse learning curves, how to interpret learning curves, the multitude of learning models, their applications and potential pitfalls, and the importance of a mathematically rigorous approach to learning curve analytics.