"There is little benefit for most students until senior high school (grades 10-12)," Walker told Life's Little Mysteries.
The research is detailed in his new book, "Reforming Homework: Practices, Learning and Policies" (Palgrave Macmillan, 2012).
Therefore, a full-time student taking four courses will devote, on average, between three to five hours per day working on coursework in addition to class time.
Although these figures may seem high compared to high school, they are not outlandish considering what you will have to do during that time.
A spokesman for the Ministry of Education (MOE) said Singapore's weekly average of 9.4 hours on homework is "fairly reasonable for upper-secondary students, who would be preparing for the national examinations".
She said: "Homework, when used appropriately, can reinforce students' learning, contribute to their progress and cultivate a healthy disposition towards learning." But in response to parents' concerns about excessive homework in recent years, schools have adopted policies to monitor and coordinate the homework load across subjects and departments.
The report was based on results from a questionnaire in 2012 for the OECD's Programme for International Student Assessment (Pisa), a test to measure academic achievement for 15-year-olds. They were asked questions about their school environment, families and attitudes towards subjects and school.
The study found that students who did more homework scored higher in Pisa.
College freshmen are usually shocked at how much time they are expected to spend on coursework outside of class.
You can expect to spend as much time on homework in college as you would at a job.