THE SUDDEN imposition of rigid centralised curriculum requirements is forcing American schools to make dramatic changes in what, and how, they teach - for the worse, according to some educators.

Backed by tough assessment tests to determine everything from teacher salaries to whether students graduate from high school, the directives are designed to pull weak schools up.

However, critics say they are actually dragging strong schools down by squeezing out the innovative work that have made them successful in favour of broad and arguably uninspiring classes.

In this environment, says Bob Schaeffer of the National Centre for Fair and Open Testing, “schools devolve into being test-preparation centres focused on the relatively narrow curriculum. The closer you get to tests, the more it’s drill-and-kill, meaning it’s mind-numbing, it stifles thinking, and it turns kids off.”

The twin tools of centralised curriculum and testing have become an obsession in the United States. As of this autumn, 49 of the 50 states now have specific centralised learning standards for English, math and science.

Forty-eight states administer assessment tests; in 27 of them, students must pass to graduate from high school. Teachers and administrators in 14 states receive financial bonuses based on how their students perform.

The goal is to identify and correct problems in America’s struggling schools, many of them in deprived inner cities, as part of the educational reform movement. Yet traditionally successful suburban schools are also being forced to conform to the mandated curriculum.

Educational reform, “like a lot of other legislation, is crafted for the whole, and yet you’re really trying to get at a part,” laments Tom Scott, director of an educational collaborative in the Boston suburbs whose members include some of the best state schools in America.

“In many of those communities, you’re seeing maybe 40 to 50 per cent of the student body going to the most competitive colleges in the country,” Mr Scott says. “There is great history and social science in middle and high schools in these communities. Their kids come home excited, stimulated about what they’re learning, and they just don’t see the necessity for destroying those programmes.”

Teachers and administrators do admit there’s room to pare some courses. But critics say tinkering with what works in successful schools will hurt far more than it will help.

“Across the country, the intellectual life is being squeezed out of schools in the name of raising standards,” says Alfie Kohn, an educational adviser and author of the book The schools our children deserve, which is being published this month.

“People without the first idea of how kids learn have adopted a top-down, heavy-handed, test-driven, business-influenced approach to raising standards, which is making great schools worse as the curriculum is hijacked in an effort to raise scores on tests.”