Teachers vary widely in effectiveness, and the best teachers can lead their students to dramatic and sometimes life-changing academic growth. Effective teachers can help students who are behind make up for lost time, achieving more than one "grade level" of academic progress in a single school year. Students placed with less effective teachers, on the other hand, often fall further behind. These effects compound over time and help to widen the gap that separates higher- and lower-performing students.

Teacher effectiveness, however, is notoriously difficult to measure. Because there are many variables that influence how much a student learns in a particular academic year, it is not always easy to fairly and accurately judge the performance of individual teachers in order to reward them for excellence or help them improve.

In 2001, as part of the No Child Left Behind Act, Washington policymakers came up with what they thought to be a solution to the challenge of teacher quality by mandating that every teacher employed by a public school be "highly qualified." It was mostly left to states to determine what "highly qualified" meant.

In most states, including Michigan, teachers are deemed "highly qualified" when they pass pedagogy and subject-area tests in their certification areas, take a certain number of credit hours of coursework in pedagogy and in certification fields (Michigan requires a major and a minor field), and jump through other certification-related hoops.

It should go without saying that there is a difference between being "highly qualified" in the NCLB sense and being highly effective. The former can be measured before the teacher ever steps into the classroom, as it is merely a matter of checking certain boxes; it focuses on inputs, such as taking particular numbers of credit hours at a teachers college, rather than on outputs such as student academic growth.

So why did the policymakers who designed NCLB ignore measures of output such as student academic growth, peer and administrator evaluations, and other indicators of on-the-job performance?

The answer is that input-based criteria such as those used in most state definitions of "highly qualified" have considerable political merit. They are objectively measurable, they do not require any significant change and therefore ruffle few feathers among the powerful and entrenched, and they transfer money from anonymous taxpayers and prospective teachers to politically well-connected teachers colleges and testing companies.

These measures go over well with teachers unions, as they allow unions to keep up the elaborate pretense that all teachers are equal, that teacher performance is not measurable, and that seniority and advanced degrees are the only grounds on which schools can fairly compensate some teachers more than others.

But by definition, input-based criteria tell us nothing about student outcomes — about what students actually learn in teachers' classrooms. By establishing criteria for teacher quality that practically all public school teachers must meet before even stepping into the classroom, and by pushing aside measures of student outcomes that might provide meaningful data about teacher effectiveness, policymakers and interest groups ensured that no uncomfortable changes in the ways teachers are evaluated and compensated would have to be considered.

With this simple maneuver, the teacher quality component of No Child Left Behind became one more entry in the ever-growing annals of meaningless and toothless — but costly — reforms of K-12 education in the United States.

We have seen many school reform initiatives come and go in recent decades, but some fundamentals have not changed. Tenure remains as strong as ever; meaningful competition between schools remains mostly absent; and the seniority-plus-credentials salary schedule remains the rule for public school teachers around the country.

Like NCLB, the Obama administration's Race to the Top initiative was treated as a major step forward by education reformers. It encouraged states (with a hefty fiscal carrot) to tweak tenure rules, change compensation structures and create a more robust labor market for teachers. But only few districts and states have had the courage to even experiment with meaningful evaluations and performance bonuses for teachers under the Race to the Top program.

Sadly, meaningful and positive reforms are the exception rather than the rule, especially reforms created at the federal level and imposed from above on an intransigent, antiquated school system in which special interests have considerable power and parents have virtually none. NCLB's notion of the "highly qualified" teacher has turned out to be yet another gimmick and smokescreen. It has proven easier to decree from above that all teachers be "highly qualified" than to engage in the more complicated and messy work of actually evaluating teachers and schools on the basis of how much is learned by the students placed in their care.

It should therefore come as no surprise that, nearly a decade after the passage of NCLB and the raft of state laws implementing its mandates, we have made no noticeable progress toward improving the overall quality of the teacher workforce or toward recognizing and rewarding our most effective teachers.

#####

Ryan McCarl is a writer and high school history teacher. He blogs about education at www.wideawakeminds.com.