According to Sir Michael, if you want a top tier education system, you recruit from your top tier of graduates:
“What have all the great school systems of the world got in common?” he said, ticking off four systems that he said deserved to be called great, in Finland, Singapore, South Korea and Alberta, Canada. “Four systems, three continents — what do they have in common?
“They all select their teachers from the top third of their college graduates, whereas the U.S. selects its teachers from the bottom third of graduates. This is one of the big challenges for the U.S. education system: What are you going to do over the next 15 to 20 years to recruit ever better people into teaching?” (NYT)