Homework doses.

After reviewing more than 60 research studies on homework between 1987 and 2003, researchers at Duke University concluded that homework does have a positive effect on student achievement.

The positive correlation was much stronger for students in grades 7 through 12 than for elementary students. The analysis also showed that too much homework can be counter-productive for students at all levels.

Findings by researcher Harris Cooper suggest that teachers should adhere to the "10-minute rule" when assigning homework. That is, for every grade the student progresses, 10 minutes of homework should be added. Therefore, a 4th grader would spend 40 minutes on homework, while a senior in high school should be working for two hours a night. More than two hours of homework in upper high school grades was not found to be associated with higher achievement.

The researchers said that teachers of younger children should assign activities that are short, require little struggle, involve parents and can relate to out-of-school activities that kids enjoy.

Cooper is the author of The Battle over Homework: Common Ground for Administrators, Teachers and Parents. Information on his research is available by calling Kelly Gilmer at 919-681-8065.