Learning curve

Hermann Ebbinghaus, the German psychologist, coined this term in 1855, to explain a mathematical graph where the vertical axis measured a person's proficiency, while the horizontal axis measured a person's experience. The resulting graph showed a high correlation between proficiency and experience. The first known usage of the term in the context of how we use it today, to explain that proficiency in any new field of learning takes time, rather like the curve on a graph, dates from the early 1900s. The expression 'a steep learning curve' to mean that a particular field of endeavour is difficult, strictly speaking, is a misuse of the concept because the steeper the curve, the higher the proficiency. In other words, a steep curve i.e. a high vertical axis, indicates high proficiency. Nevertheless, 'steep learning curve' has become a popular usage for something that is difficult to learn since the 1960s.