Our site's global leaderboard (https://www.albert.io/leaderboard) is ranked based on points. Students earn points by answering questions correctly on their first attempt on that question.
Incorrect first attempts one point, whereas correct answers on first attempts earn anywhere from 5-50 points depending on the subject and question difficulty.
The global leaderboard can be scoped by school year and subject to refine it.
In the near future, we will be allowing teachers and schools to have school and class-specific leaderboards.