Classroom heroes like Robin Williams in “Dead Poets Society” or Michelle Pfeiffer in “Dangerous Minds” are endowed with exceptional, innate inspirational powers. Government policies, which often start from the same assumption, seek to raise teaching standards by attracting high-flying graduates to join the profession and prodding bad teachers to leave. Teachers’ unions, meanwhile, insist that if only their members were set free from central diktat, excellence would follow…

Education has a history of lurching from one miracle solution to the next. The best of them even do some good. Teach for America, and the dozens of organisations it has inspired in other countries, have brought ambitious, energetic new graduates into the profession. And dismissing teachers for bad performance has boosted results in Washington, DC, and elsewhere. But each approach has its limits.

Teaching is a mass profession: it cannot grab all the top graduates, year after year. When poor teachers are fired, new ones are needed—and they will have been trained in the very same system that failed to make fine teachers out of their predecessors…

What teachers fail to learn in universities and teacher-training colleges they rarely pick up on the job. They become better teachers in their first few years as they get to grips with real pupils in real classrooms, but after that improvements tail off. This is largely because schools neglect their most important pupils: teachers themselves.

Across the OECD club of mostly rich countries, two-fifths of teachers say they have never had a chance to learn by sitting in on another teacher’s lessons; nor have they been asked to give feedback on their peers…

Good teachers set clear goals, enforce high standards of behaviour and manage their lesson time wisely. They use tried-and-tested instructional techniques to ensure that all the brains are working all of the time, for example asking questions in the classroom with “cold calling” rather than relying on the same eager pupils to put up their hands.