I think Goodhart's law is closest to what he is getting at. There is also the aphorism of Deming, that the most important figures for managing your business are unknown and unknowable. We want to measure successful learning. Instead, we measure test scores. Whatever figures actually measure successful learning are unknown and likely unknowable. "Management", in this case the parents, teachers and administration, are focused on test scores and other marks of achievement. College admissions departments have their own measures that may include all of these things. But, in the end, hitting high values for these targets may not be reaching the actual goal. It's a good way of looking at an age-old problem.