Feb. 22 (Bloomberg) -- U.S. high school students are showing no overall improvement on a nationwide achievement test, even as they take more challenging courses and earn higher grades, the U.S. Education Department reported.

Nationwide, 73 percent of 12th-grade students achieved a ``basic'' reading score in 2005, down from 80 percent in 1992, according to the National Assessment of Educational Progress, a sampling test the government calls the ``nation's report card.'' Sixty-one percent scored at or above the basic level in math.

At the same time, 68 percent of high school graduates completed at least a ``standard'' curriculum, up from 59 percent in 2000, with the overall grade point average about one-third of a letter grade higher than in 1990, the department said in a report. The figures raise questions about the quality of the courses being taught at U.S. high schools, it said.

``If, in fact, our high school students are taking more challenging courses and earning higher grades, we should be seeing greater gains in test scores,'' U.S. Education Secretary Margaret Spellings said in a statement. The results ``show that we have our work cut out for us,'' she said.

In May, NAEP said there were declines in science scores for high school students. Among 12th-graders, 54 percent were at or above the basic level in science in 2005, statistically similar to 2000 and a decline from 57 percent in 1996, the report said.

`Disappointing' Results

Business and education leaders said the latest results reinforce fears that the U.S. school system isn't preparing its students to be competitive in the global workplace.

``It's disappointing and unacceptable,'' said Susan Traiman, director of education and workforce policy at the Business Roundtable, a Washington-based association of chief executive officers of U.S. companies including General Motors Corp., Exxon Mobil Corp. and Citigroup Inc.

``These numbers perfectly book-end the rating of employers last fall,'' who in a nationwide survey said more half of companies are finding workers inadequately training in math or reading, said Linda Barrington, labor economist and research director at the Conference Board, a New York-based business group.

Bush Budget

Today's report on reading and math follows President George W. Bush's release earlier this month of his fiscal 2008 budget recommendation, in which he again asked Congress to devote a greater share of federal funding toward raising high school achievement levels.

Congress hasn't endorsed that plan in the past, in part because Democrats opposed Bush's calls for financing high school improvements through spending cuts in other parts of the federal education budget.

Representative Buck McKeon, the California Republican who headed the House education committee last year, believes the NAEP results mean Congress must continue to demand more from schools, spokesman Steve Forde said.

The NAEP report ``is a further indication that backing away from that commitment would be a huge mistake,'' Forde said.

Others were more cautious. Some of the lower performance at the 12th-grade level could be due to older students realizing their scores on the NAEP test have no effect on their personal records, said Antonia Cortese, executive vice president of the 1.3 million-member American Federation of Teachers, the nation's second-largest teacher union.

`No Child' Testing

The federal No Child Left Behind law currently requires schools to test students in grades 3 through 8, then once in high school. Researchers including Bruce Fuller, an education professor at the University of California, Berkeley, have suggested that states may be weakening their tests to help raise their passing rates under the federal law.

The NAEP reports today may reinforce fears that the quality of high-level courses suffers as more students are allowed into them, the Education Trust, a Washington-based research and advocacy group, said in a statement. ``This pattern is undoubtedly playing out in some schools,'' Education Trust said. ``But we know that it doesn't have to be this way.''

The NAEP tests for 2005 were given to a nationally representative sample of more than 21,000 high school seniors in 900 schools.

The results show 35 percent of 12th-grade students scored at or above ``proficient'' in reading in 2005, down from 40 percent in 1992. Only 23 percent of 12th-graders achieved the proficient rating in math in 2005.

Math Scores

The math scores aren't comparable with previous years because NAEP introduced a new assessment test in 2005, the report said. A separate analysis provided by NAEP of common math questions, however, showed a ``statistically significant increase,'' to 44 percent in 2005 from 42 percent in 2000, in the percentage of students answering each question correctly.

The scores released today also showed persistent gaps among racial and ethnic groups, including white students scoring 31 points higher than black students in math and 24 points higher than Hispanic students.

The comparisons to high school transcripts were based on data from 26,000 graduates of about 640 public schools and 80 private schools. The report defined a ``standard curriculum'' to mean the student has taken at least four credits of English and three each in social studies, mathematics and science.

In addition to more students enrolling in such a curriculum and receiving higher grades, the NAEP study found that U.S. high school graduates in 2005 earned about three credits more than their 1990 counterparts. That translates to about 360 additional hours of instruction during their high school years, it said.

Possible reasons for the increase in high school grades include ``grade inflation, changes in grading standards and practices and growth in student performance,'' the report said.

To contact the reporter on this story: Paul Basken in Washington at pbasken@bloomberg.net.

Last Updated: February 22, 2007 18:28 EST