# Predicting Student Learning Curve - (Croteau, Heffernan, & Koedinger, 2004). - The learning curve of a [Knowledge Component](Knowledge%20Component.md) graphs the durations of its learning events (or their probability of error). - a learning curve should be a smoothly descending power-law or exponential curve - For instance, the first [Learning Event](Learning%20Event.md) for a [Knowledge Component](Knowledge%20Component.md) may take 50 seconds, because the student is constructing the [Knowledge Component](Knowledge%20Component.md) by referring to the textbook and asking the tutoring system for help. The next [Learning Event](Learning%20Event.md) might take only 25 seconds because the student is reconstructing the [Knowledge Component](Knowledge%20Component.md). On the third [Learning Event](Learning%20Event.md), the student recalls the [Knowledge Component](Knowledge%20Component.md) after a brief struggle, so the event takes 12 seconds. The fourth event takes 6 seconds, the fifth takes 3 seconds, and so on. However, if the representation of knowledge is inaccurate, a [Knowledge Component](Knowledge%20Component.md)'s learning curve may have a huge jump in the middle or be quite jagged