Fuzzy Math

I taught math for 18 years but the formula used in this ranking of the top high schools in the country still doesn’t make sense to me. My confusion has nothing to do with the mathematics and everything to do with how it’s used.

The Challenge Index assigns a value to each school by taking the “ratio of AP or IB tests taken by all students divided by the number of graduating seniors”. After reading the article four or five times I’m still at a loss to see how that formula could possibly be used to declare one school “better” than another. The number of students taking these tests says nothing about the quality of teaching in those classes not to mention the support given to the kids that don’t take advanced classes. And it totally ignores all the other high school programs (music, drama, community service, etc.) that are essential both for student learning and for creating balanced people.