The concept of flipped instruction appears to be catching on in classrooms nationwide, as more teachers say their students are benefiting from the technique. In 14 Cincinnati-area schools, teachers -- including seventh-grade world history teacher James Zoller -- are experimenting with the technique. A recent survey on flipped instruction found that among teachers who have utilized it, most report increased student achievement. The technique, however, has drawn criticism from some who say not all students have equal access to technology at home.