[ComfortEagle]

They came up with something called the "Challenge Index" which is basically rates each school's participation in AP, IB, and Cambridge tests.

They take the total number of AP tests taken each year and then divide them by the number of graduating seniors, so bigger schools would not have an advantage over smaller schools.

Their belief is that just taking the AP course and test is valid enough, none of the AP test scores were factored in. They said those who participated in AP courses, whether they passed the tests or not, learned a great deal more.