I remember years ago being given these quizzes/tests in school by a third party testing company.
We deliberately gave false answers. The teachers left the room when the testers arrived, and we had a free-for-all with them.
Fun times, but not an accurate measure of what we really knew.
I can tell you from having taught in college classrooms that it is entirely accurate. Williams, himself, is in the classroom everyday. Unlike many professors, he enjoys teaching and makes a point to teach at least one lower or entry level course every semester. He isn’t in some think tank doing his own thing. He speaks from authority on this matter.