Why I don't talk about learning curves

I don’t want to pick on this person, so I won’t use their name, but I saw this in a blog post today:

The most common complaint people have when learning Haskell is the steep learning curve.

It’s a very typical example of a mistake I see all the time, which is that when people say something has a steep learning curve, they mean that it’s difficult to learn. It’s understandable why people would think that way – steep things are difficult to climb.

However, the X axis on the plot of a learning curve is the resources invested, and the Y axis represents the level of mastery attained. You can look it up. So a steep curve means that initial progress in learning is very rapid. The fuller definition of a steep learning curve is that initial progress is rapid but that the curve plateaus and progress becomes difficult.

Unfortunately, the rampant misuse of “steep learning curve” means that if I use it correctly, nobody will actually get what I’m talking about. If I use it incorrectly, then I’m part of the problem. The end result has been to discourage discussion of learning curves using that terminology at all. Nobody seems to mind.