In the end, teachers, like other professionals, have a genuine interest in safeguarding the standards and reputation of their profession. Even the most urgent efforts to translate a government-established curriculum into classroom practice typically drag out over a decade, because it takes so much time to communicate the goals and methods through the different layers of the system, and to build them into teacher-education programmes. When what and how students learn changes so rapidly, this slow implementation process leads to a widening gap between what students need to learn, and what and how teachers teach. Subject-matter content will be less and less the core and more and more the context of good teaching.