Too much homework can be counterproductive
"Instead of improving educational achievement in countries around the world, increases in homework may actually undercut teaching effectiveness and worsen disparities in student learning, according to two Penn State researchers.
Most teachers worldwide are not making efficient use of homework, said David P. Baker, professor of education and sociology. They assign homework mostly as drill, to improve memorization of material either in math, science or the humanities. While drills and repetitive exercises have their place in schooling, homework may not be that place."