In this morning’s Post, Jay Mathews attempts to explain the “method” to the “madness” behind his “much-maligned” Challenge Index. [I’m tired of explaining the index. Read any of my past rants if you don’t know what this is.]

Instead he simply relates a short history of the path to his enlightenment concerning the power of the Advanced Placement program to completely reform American high schools.

However, he still misses the point that creating a list of the best schools based exclusively on the number of tests taken by students is a very poor measuring device.