A consensus is emerging on what those best practices are, and they have little to do with test-driven instruction. Research by Linda Darling-Hammond, a Stanford University teaching expert and former Obama adviser, has found that in Finland, South Korea, and other high-performing nations, teachers spend just 50 percent of their workday in the classroom with students, compared to about 80 percent for American teachers. During the rest of their day, Finnish and South Korean teachers work with other adults to plan lessons, observe one another's classrooms, and evaluate student work. This balance is especially important for beginning teachers; powerful evidence suggests that the single most helpful teacher-training exercise is to spend time inside a master teacher's classroom and to get feedback from that master teacher on one's own practice.
