t is difficult to dislodge the educational establishment. In New Orleans, a hurricane was required: since Katrina, New Orleans has made more educational progress than any other city, largely because the public-school system was wiped out. Using nonunion charter schools, New Orleans has been able to measure teacher performance in ways that the teachers' unions have long and bitterly resisted. Under a new Louisiana law, New Orleans can track which ed schools produce the best teachers, forcing long-needed changes in ed-school curricula