"Steep learning curve. Scores of authors use the phrase “steep learning curve” or “sharp learning curve” in reference to a skill that is difficult to master. For example, when referring to the difficulty of learning a complex surgical procedure (endoscopic pituitary surgery), one author team contended that it “requires a steep learning curve” (Koc et al., 2006, p. 299). Nevertheless, from the standpoint of learning theory, these and other authors have it backward, because a steep learning curve, i.e., a curve with a large positive slope, is associated with a skill that is acquired easily and rapidly (Hopper et al., 2007)."<p>Curve does not mean "slope". I feel like it's the "learning theory" folks that aught to change their terminology for this one.