A LITTLE OVER a year ago New York became the first state to enact a so-called truth-in-testing law. It requires people who give standardized tests to disclose the questions, answers sheets and correct answers after a test each time one is given. This means that the testing companies must design and calibrate a great many more versions of each test, causing costs to go up.

One immediate result of the law's passage in New York was that 20 of the 26 testing organizations that had been giving tests in the state withdrew, leaving students to travel to neighboring states. The Association of American Medical Colleges challenged the constitutionality of the law and was granted an injunction. This past summer the legislature backed off, passing several amendments that exempt most of the smaller testing enterprises from the law's requirements.

However, by far the most important of the tests -- the pre-college Scholastic Aptitude Test -- has been operating under the new rules. The College Board has now released early results that give some idea of whether the law in fact accomplishes the purposes for which it was intended. The figures cover the 118,000 students who took the SAT in New York last spring. Though students were informed of their new rights, as of mid-September fewer than 5 percent had requested copies of the tests and answers. The number was way below expectations, but the real irony lies in who these students were.

They were not the marginal students whose educational future was pictured as hanging on the thread of a single uncertain test score. Nor were they minority and disadvantaged students. Those who requested copies of the tests were, according to information voluntarily supplied by the students, twice as likely to be in the top tenth of their class as those who didn't ask. Their scores on the SAT were 60 to 80 points higher than the non-requesters. Their median family incomes were $32,000, compared with $24,000 for all students. In short, they were the highly motivated, higher scoring, high achievers.

A great many interesting questions remain. What use do students who request copies of the test make of them? Do they merely check to make sure they were given the correct score or do they work through the questions they got wrong? Since most of the students in this group were juniors, will those who requested the tests do better this fall when they take the SAT as seniors than those who did not request their tests?

The evidence is not all in, but so far it points to a negligible educational effect of the law's disclosure requirements. If anything, its social impact appears to be the opposite of what was intended -- widening rather than narrowing the gap between the most and least successful students. The only indisputable effect so far has been to raise the cost of testing for everyone.