In 2006, hardly anyone had ever heard the phrase “flipped classrooms.” By 2019, the phrase was frequently used by policymakers, administrators, and teachers (see Ngram viewer).

Of course, thoughtful teachers past and present have done versions of “flipped classrooms” before it became the reform du jour. Many teachers have regularly assigned work for students to do at home thus allowing extended and in-depth discussions during precious classtime. Nothing new here. Rediscovering what was once an innovation occurs again and again.

Where “flipped classrooms” become more difficult to implement are in those schools where many teachers see this innovation as piling on more work for them in reading and grading student homework and preparing for deeper class discussions of a topic. Moreover, there are schools with large numbers of students who have never experienced “flipped classrooms,” come from homes where doing homework is a hill to climb, care little for…