The importance of individual teachers has emerged in sharp focus over the past decade, with compelling evidence that teachers have large effects on a range of student outcomes. Wide variability in teacher effectiveness, both across and within schools, highlights the persistent challenge of providing students with access to high-quality teachers. However, traditional efforts to increase teacher quality through professional development (PD) have been largely ineffective. That may be changing, as a new form of PD, teacher coaching, has emerged to disrupt the PD industry.
Historically, PD has been dominated by daylong seminars that took teachers out of the classroom and delivered the same tips and tricks to an entire department, grade level, or school. But as research has found, these programs to have little or no effect on teacher quality. Some training has shifted to a customized, smaller-scale approach: instructional coaching, whereby an expert mentor works one-to-one with teachers to provide a steady stream of feedback and suggest new techniques based on frequent classroom observations. By the 2015‒16 school year, 27 percent of public K‒12 schools reported having a reading coach on staff, 18 percent had a math coach, and 24 percent had a general instructional coach, according to the National Teacher and Principal Survey.