Is Homework Beneficial?
Homework improves student achievement.
Studies show that homework improves student achievement in terms of improved grades, test results, and the likelihood to attend college.
Research published in the High School Journal indicates that students who spent between 31 and 90 minutes each day on homework "scored about 40 points higher on the SAT-Mathematics subtest than their peers, who reported spending no time on homework each day, on average." 
On both standardized tests and grades, students in classes that were assigned homework outperformed 69% of students who didn't have homework.  A majority of studies on homework's impact - 64% in one meta-study and 72% in another - showed that take home assignments were effective at improving academic achievement. 
Research by the Institute for the Study of Labor (IZA) concluded that increased homework led to better GPAs and higher probability of college attendance for high school boys. In fact, boys who attended college did more than three hours of additional homework per week in high school. 
Too much homework can be harmful.
A poll of high school students in California found that 59% thought they had too much homework.  43% of respondents said that homework was their greatest source of stress, and 82% agreed that they were "often or always stressed by schoolwork." 
The American Educational Research Association says that "whenever homework crowds out social experience, outdoor recreation, and creative activities, and whenever it usurps time that should be devoted to sleep, it is not meeting the basic needs of children and adolescents." 
High-achieving high school students say the amount of homework they have to complete leads to sleep deprivation and other health problems such as headaches, exhaustion, weight loss, and stomach problems. 
Excessive homework leads to cheating: 90% of middle school students and 67% of high school students admit to copying someone else's homework,  and 43% of college students engaged in "unauthorized collaboration" on out-of-class assignments.  Even parents take shortcuts on homework: 43% of those surveyed admitted to having completed a child's assignment for them.