### Khan Academy: Machine Learning → Measurable Learning

With millions of problems attempted per day, Khan Academy’s interactive math exercises are an important and popular feature of the site. (Math practice. Popular. Really!) For over a year, we’ve used a statistical model of each student’s accuracy on each exercise as the basis for awarding *proficiency*. When a user reaches a high enough accuracy on an exercise, we award the proficiency badge, which is both a reward for the student’s accomplishment and a signal that they can move on to learn even cooler math. So it’s important that we are intelligent about when we suggest a that a student moves on… and when we don’t.

This post details recent improvements we have made in the accuracy of the statistical model, and provides evidence that use of the improved model has led to increased learning gains.