The Supreme Court upheld the common schoolroom practice of having one student grade another's work, ruling Tuesday that such paper-swapping does not violate federal privacy law.

The 9-0 ruling ends a challenge filed by a mother whose learning-disabled son was ridiculed as a "dummy" when his poor grades were read aloud to classmates.

Teachers nationwide commonly tell students to swap homework, quizzes or other schoolwork and then correct one another's work as the teacher goes over it aloud. Sometimes the teacher then has students call out the results, and the teacher records them.

"Correcting a classmate's work can be as much a part of the assignment as taking the test itself," Justice Anthony M. Kennedy wrote for himself and seven colleagues. Justice Antonin M. Scalia filed a separate concurring opinion.

"It is a way to teach material again in a new context, and it helps show students how to assist and respect fellow pupils," wrote Kennedy, a former law professor who still teaches several classes a year.

Kristja Falvo won a lower court decision that banned classroom grading aloud as a violation of a 1974 law that gave parents veto power over the release of student "education records."

At issue for the Supreme Court was whether the results of a pop quiz or other classwork is considered a record under the law. The Owasso, Okla., school district Falvo's children attend argued that such a broad interpretation could outlaw the school honor roll, or even the practice of working out a math problem on the blackboard. The Bush administration backed the school district.

Falvo's lawsuit became an ideological contest between the rights of parents and the rights of teachers to run their classrooms, and between social conservatives and teachers' unions.

Kennedy, who asked during oral arguments last year if privacy law would forbid the awarding of gold stars for good work, said that the 10th U.S. Circuit Court of Appeals Court's rationale in this case would vastly expand teachers' workloads.

Teachers would have to maintain separate records for each student, rather than a universal grade book, and students who graded even their own papers would become legal custodians of those records, Kennedy noted.

Further, applying federal privacy law that way would erode the principle that education is a local matter, Kennedy wrote.

"The court of appeals' logic ... would effect a drastic alteration of the existing allocation of responsibilities between states and the national government in the operation of the nation's schools," Kennedy wrote.

Falvo's 1998 lawsuit claimed that paper-swapping violated students' civil rights. A federal judge threw out the case, but the Denver-based appeals court reinstated it in a ruling that focused on a 1974 educational privacy law.

The Bush administration argued that in passing the law, Congress was concerned with preserving the privacy of final, institutional records of a school, not the results of one day's classwork.

The case is Owasso Independent School District v. Falvo, 00-1073.