It is computed by the test publisher as the national average for the children in that school grade in the nation at large.

Even the test publishers have said their exams shouldn't be used in isolation to promote or retain students.

The test publisher denied any error.

We accepted all the 2001 scores but agreed with our test publisher that the 2000 sixth-grade scores were too high.

Some studies offer partial support for the test publishers' claims.

The company later moved to New York, where it became a test publisher.

"The students' answers will be recorded into the test publisher's scoring system," the Education Department said in a statement.

But even with the ability to offer bonuses, stock options and profit sharing, the major test publishers are struggling, too.

Mr. Arnold recommended asking three basic questions when choosing a test publisher.

Be skeptical of test publishers claiming near-perfect accuracy.