Yes, even traditional teaching in public schools has changed. Incremental alterations in teacher-directed lessons have occurred over the past century. In the technologies used during lessons, managing student behaviors in large to small groups, crafting in-class assessments, and many other instances of common teaching practice, teachers have adapted and adopted innovations that have altered their teaching.

These incremental changes, however, are not the fundamental shifts in teaching that Progressive, constuctivist, and student-centered learning boosters have sought over the past century. Except in scattered classrooms and schools across the country, some teachers and principals have created fundamentally different classroom practices, say, from teacher-directed to student-driven (see here, here, and here), but most classrooms in the U.S.–or anywhere else in the world, for that matter–continue to have teacher-directed lessons.

Why is that?

Some researchers look at the constancy of teacher beliefs over time to answer the question. Those researchers…