Is a teacher who is certified to teach all sciences really prepared to teach any science? As NCTQ found in the All-Purpose Science Teacher, broadly defined certifications mean that many classrooms are lead by "highly qualified" teachers who may not actually know much about the content of the course they are teaching. 

New figures from the National Center for Education Statistics show that slightly less than half of social studies and science classes are lead by teachers who majored in the subject they are currently teaching, even though 80 percent are certified. Seventy percent of chemistry classes, for example, are taught by science-certified teachers, but only half of these teachers majored in chemistry. 

NCTQ does not believe teachers must major in the subject area they teach, but that they should nonetheless have strong content knowledge in that field. This is unlikely, however, in the 40 states which allow the broad-field or multiple-subject science certifications. In these states it's possible to fail the physics questions on the state certification exam, still pass the test overall, and emerge as a fully credentialed science teacher, qualified to teach physics. The same is often true for social sciences certification. Our 2011 State Teacher Policy Yearbook, to be published in January 2012, will explore this topic further.