New Study Supports Using Test Scores in Teacher Evaluations

Tom Moran | The Star-Ledger
01/06/12

 Just as New Jersey prepares to revamp its tenure laws, an exhaustivenew study on teacher quality indicates that Gov. Chris Christie is on the right track.

The study’s conclusion is simple: Getting rid of the worst teachers, and holding onto the good ones, leads to lifetime benefits for their students. And test scores are a tremendously helpful tool in helping to evaluate teacher performance.

The study, by a team of economists at Harvard and Columbia universities, tracked 2.5 million students over 20 years. When they started the study, the economist expected to find that judging teachers in part on test scores was a big mistake.

But they found just the opposite, that tests are telling. Understand that it’s not a simple matter of crediting teachers whose kids score the highest. That would reward a lazy teacher who is lucky enough to have classrooms full of attentive kids with supportive families, and punish a heroic teachers who works with the state’s poorest kids.

Instead, the study measured the impact a teacher had on a classroom full of kids, taking into account where they began. So a teacher who helps poor kids read more effectively gets credit, even if the students remain behind grade level. It’s known as “value-added ratings” and several school districts across the country have begun using it in teacher evaluations.

No one wants to rely exclusively on test scores. There is no substitute for classroom visits. And checking lesson plans and other nuts and bolts of the profession is important as well.

But the teachers union, and many obedient Democrats in the Legislature, are resisting all use of test scores in teacher evaluations.

Perhaps this study can help change their minds. It finds that the kids who attended classes with effective teachers were more likely to avoid teen pregnancy, attend college and to earn more money later in life.

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