I do not find the excerpt you provided, in the article posted above. Possibly it is in a different article?
The article you posted
https://www.educationnext.org/what-...-americas-most-challenging-high-schools/"Occasionally principals would tell me they didn’t need AP, IB or Cambridge. They said they could make their own courses just as demanding. I determined that rarely happened because their homemade final exams were not written or graded by independent experts outside the school, as AP, IB and Cambridge exams were. If classroom teachers controlled the tests, they tended to be gentle with those nice students they knew. That ruined the principals’ hopes for tough grading and high standards."
No evidence to support.
(I have also had many conversations with him)
Got it! You were quoting from the OP article, not an article you linked in your post.
In context, Jay Mathews admits he first created the "Challenge Index" as a stunt to help sell a book, but as he looked more deeply into the numbers, he found that test scores from AP exams and other standardized tests were more meaningful for comparison than scores on locally written classroom tests. In a retrospective article looking back over 23 years, some may say it would not be necessary to prove or substantiate each point that his decades of experience have taught him.
On a related theme, a
recent thread discussed the value of test scores from independent sources... SAT, ACT, and AP exams... for the college application process.
