Julia Keleher, Puerto Rico's education secretary, stood in front of a school library full of high school students and asked them to do something students in Puerto Rico's public schools aren't often asked.
"Take out your phones," she said. "Look up the definition of charter school."
A girl's hand shot up.
"A charter school," the girl read, "is a school that receives government funding but operates independently of the established state school system in which it is located."