Stephen Sawchuk’s recent Ed Week article on the new wave of teacher evaluation systems—and the high ratings they're generating—has likely left many reformers scratching their heads.

Stephen points out that in states like Tennessee and Florida, which are hotbeds for Michelle Rhee–type teaching policies, the vast majority of teachers are quite effective. Even in Florida, where teachers are judged by standardized test score gains, 97 percent received top ratings. In Tennessee’s new system, more than 16 percent of the teachers were rated with the lowest score on test score measures. Only 0.2 percent of those observed by principals were categorized as ineffective.

While there are many policymakers—and virtually all of our nation’s 3.2 million teachers themselves—who want to see more rigorous and valid evaluation systems that strengthen teaching practices, there are also reformers who want nothing more than to identify ineffective teachers and dismiss them. But overall, we need to shift our focus from what's not working for the ineffective minority to how we can ensure continued growth for the effective majority.

Although scholars have long pointed out the problems of current teacher evaluation systems (see Art Wise and Linda Darling-Hammond’s 1984 research (PDF) and its seminal findings), there is still much to learn about the validity of the programs that are being put into place today.

Even when pains are taken to create a fair and reliable ratings system, such as the Measures of Effective Teaching project, flaws still abound. Jesse Rothstein and colleagues found that in each of the multiple measures (standardized test score gains, classroom observations, and student engagement ratings) used in the carefully designed project reflects a distinct dimension of teaching. They also noted that “none of the three types of performance measures captures much of the variation in teachers’ impacts on alternative, conceptually demanding tests.”

What none of these analyses suggest is how teachingconditions must change before we can design and implement a valid and reliable evaluation system.

Both principals and teachers must have more time to look carefully at the data and make sense of it. In top-performing nations like Singapore, teachers only teach students 18 to 20 hours a week. Here in the U.S., we devote little organizational space to assembling sound evidence, analyzing it, and applying professional judgment to determine who is effective and why—and how to help them get better.

In Singapore there is no obsession with standardized test scores. Teachers are evaluated on how they nurture the child, work with parents, and care for both the heart and mind. In Singapore, evaluation is not a number (or three of them); it is a narrative that encourages teachers to expand their teaching repertoire, select a career track, and take those developmental actions that lead to greater competence and higher levels on a career lattice. Teachers’ evaluations are based on the experience level of the teacher, since the level of competence expected of a new teacher is much lower than expectations for senior teachers. But most importantly, the evaluations don't just assess current performance. They also consider a teacher’s potential.

Will policymakers start viewing evaluation differently? I suspect they will, if only they listened more carefully to the millions of teachers nationwide who want an evaluation system that will genuinely improve their practice and their students’ learning.