Data from the U.S. Department of Education suggest there may be a point at which increasing amounts of homework assigned to students result in diminishing returns.

Researchers correlated U.S. eighth-graders' math scores with the number of hours of homework they accomplished. Then the results were compared with similar studies of homework in several other countries.

• Scores peaked for U.S. students when they did about one hour or more of homework nightly - while at two to three hours they declined.

• In Japan, additional hours beyond one increased math scores -- but only slightly.

• Canadian students benefited from one to two hours of homework -- but when they worked more, their scores were about equal to when they worked for only one hour.

• German students seemed to do slightly better when they toiled for two to three hours a night -- but scores plunged when they were subjected to three or more hours.

Source: Peter Brimelow, "Charticle: Too Much Homework?" Forbes, December 25, 2000.