Until recently, teacher quality was largely seen as a constant among education’s sea of variables.
Policy efforts to increase teacher quality emphasized the field as a whole instead of the individual:
for instance, increased regulation, additional credentials, or a profession modeled after medicine
and law. Even as research emerged showing how the quality of each classroom teacher was crucial
to student achievement, much of the debate in American public education focused on everything
except teacher quality. School systems treated one teacher much like any other, as long as they
had the right credentials. Policy, too, treated teachers as if they were interchangeable parts, or
“widgets.”
