From Education Week by Erik Robelen:
U.S. student achievement looks more favorable on the global stage when comparisons take into account the especially large share of American adolescents who come from disadvantaged social backgrounds, concludes a study released today by the Stanford Graduate School of Education and the Economic Policy Institute. The gap, for instance, between U.S. students and those from top-scoring nations on one prominent global assessment would be cut in half in reading and by at least one-third in math, the study says, if statistical adjustments were made for social class.

In addition, the study finds that while the achievement of disadvantaged U.S. students has been "rising rapidly over time," test scores for such students in some nations to which the United States is frequently compared, such as Finland and South Korea, have been "falling rapidly."

The research, which draws on reading and math results spanning a decade or more on two high-profile international assessments, seeks to go beyond the average national test scores widely discussed and debated to better gauge how countries are educating particular groups of students, especially those who tend to face the biggest academic challenges.

"Education reformers frequently invoke the relatively poor performance of U.S. students to justify school policy changes," write co-authors Richard Rothstein of the Economic Policy Institute, a Washington think tank, and Martin Carnoy, an education professor at Stanford. But those conclusions draw on comparisons that are "oversimplified, frequently exaggerated, and misleading. They ignore the complexity of test results and may lead policymakers to pursue inappropriate and even harmful reforms."

Central to the new research is the premise that, in every country, students at the bottom of what the researchers call the "social-class distribution" perform worse, on average, than students higher in that distribution. And so, the U.S. average is brought down relative to some other nations with which the United States is frequently compared "because we have so many more test-takers from the bottom of the social-class distribution."

The study focuses on achievement in the United States and six other countries. They include three high-fliers on global comparisons—Canada, Finland, and South Korea—as well as three "similar post-industrial countries": France, Germany, and the United Kingdom.

The study comes as a fresh batch of international achievement data was issued in December on TIMSS, the Trends in International Mathematics and Science Study, and PIRLS, the Program for International Reading Literacy Study. Here's the EdWeek coverage on the new global data.

The authors say that "social-class inequality" is greater in the United States than in "any of the countries with which we can reasonably be compared." As a result, the relative performance of U.S. adolescents is "better than it appears when countries' national average performance is conventionally compared."

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