Study Disputes 'Plateau Effect' in Test Scores

One of the common beliefs about testing in the era of accountability hinges on the notion that student test scores improve rapidly in the first few years of a new testing program as teachers and students adjust, followed by a “plateau” in scores after the early gains.

The assertion underpins criticism of the federal No Child Left Behind Act, which requires states to raise scores regularly over a 12-year period.

But a new study , released yesterday, offers evidence that while this “plateau effect” in test scores does appear in some states, it is not...