One of the world's foremost experts on comparing national school systems told members of Congress yesterday that many other countries were surpassing the United States in educational attainment, including Canada, where he said 15-year-old students were, on average, more than one school year ahead of American 15-year-olds.

America's education advantage, unrivaled in the years after World War II, is eroding quickly as a greater proportion of students in more and more countries graduate from high school and college and score higher on achievement tests than students in the United States, said Andreas Schleicher, a senior education official at the Organization for Economic Cooperation and Development in Paris, which helps coordinate policies for 30 of the world's richest countries.

“;Among OECD countries, only New Zealand, Spain, Turkey and Mexico now have lower high school completion rates than the U.S.,”; Schleicher said. About 7 in 10 American students get high school diplomas.

Schleicher's comments came in testimony before the Senate education committee and in a statement he delivered. The panel plans to rewrite the Elementary and Secondary Education Act, the main law governing federal policy on public schools.

The committee also heard from Dennis Van Roekel, president of the National Education Association, the largest teachers' union; John Castellani, president of the Business Roundtable, a group that represents corporate executives; and Charles Butt, chief executive of a supermarket chain in Texas, who said employers there faced increasing difficulties in hiring qualified young workers.

The blame for America's sagging academic achievement does not lie solely with public schools, Butt said, but also with dysfunctional families and a culture that undervalues education. “;Schools are inheriting an overentertained, distracted student,”; he said.

Sen. Tom Harkin, D-Iowa, who leads the Senate Committee, picked up on that comment. “;Overentertained and distracted — that's right,”; Harkin said. “;The problem lies with many kids before they get to school, and if we don't crack that nut, we're going to continue to patch and fill.”;

Schleicher based many of his international comparisons on data from the OECD Program for International Student Assessment, which tests students in scores of countries every three years in math, reading or science.

He said Finland had the world's “;best performing education system,”; partly because of its highly effective way of recruiting, training and supporting teachers.

South Korea, he said, which was in economic ruin after World War II, today is an economic dynamo partly because of its educational attainment, which, among other measures, has achieved a 96 percent high school graduation rate, the world's highest.

Poland, Schleicher said, is improving its education system most rapidly. In less than a decade, it raised the literacy skills of its 15-year-olds by the equivalent of almost a school year. “;If the U.S. would raise the performance of schools by a similar amount,”; he said, “;that could translate into a long-term economic value of over 40 trillion dollars.”;

America's system of standards, curriculums and testing controlled by states and local districts with a heavy overlay of federal rules is a “;quite unique”; mix of decentralization and central control, Schleicher said. More successful nations, he said, maintain central control over standards and curriculum, but give local schools more freedom from regulation, he said.

“;The question for the U.S. is not just how many charter schools it establishes,”; he said, “;but how to build the capacity for all schools to assume charter-like autonomy, as happens in some of the best-performing education systems.”;

“;In one way, international education benchmarks make disappointing reading for the U.S.,”; he said.